Wiring up a house battery from a 24v system.

Having recently joined a group that discusses DIY camper builds I realized the need to point out how to get a 12v feed from a 24v system. It seems pretty easy when you first think of it - if your truck has 24v then it has two 12v batteries connected together in series, why not simply connect a wire to middle of the connection then you have 12v and the alternator will charge it right?

WRONG!

A 24v system gets charged by a ground at one end and 28 volts at the other end - nothing goes to the centre. Think about it this way, the alternator charges with a current. In a very simplistic way imagine drawing 10 amps from the 12v centre point while the alternator charges at 20 amps. So we have 20 amps going through the “upper battery” [24v output] while the “lower battery” [12v connection] has 20 amps going to it as well but is sharing 10 amps with the house battery connection, so it only has 10 amps going through it. Realistically the lower battery will slowly get flatter than the upper battery. Depending how much you actually draw from that 12v centre tap, after a while its voltage will be lower then the upper battery until eventually, instead of them both being around 12.8v when fully charged, it will be flat at 11.8 volts while the upper battery will be around 13.8 volts.

The one battery gets destroyed internally as the acid sits in the plates while the other battery gets damaged by overcharging. This will be a very costly mistake as both batteries will need to be replaced.

This image is a very simplistic depiction of the actual variables but gives the general idea.

Besides the damage that this approach causes to the batteries on the long term, if you were to run your house battery flat overnight, or several days without any driving, the truck will not start again due to one flat battery, leaving you with 12 volts to start a 24 volt truck.

Ideally two alternators, one 12 volt and one 24 volt, could keep the truck batteries separate from the house battery and charge both correctly, but it’s not always practical to implement.

You CAN connect a pickup from the 12 centre-tap of the truck batteries BUT you will need two devices. A VSR [voltage sensitive relay] and a charge-equalizer [or ‘even charger’]. The VSR connects the house battery to the 12v pickup of the truck batteries when the engine is running and the charging alternator increases the voltage. Then when the engine is turned off, about a minute later the battery voltage drops low enough to disconnect the house battery meaning you can’t flatten the truck battery.

The other important device is a charge equalizer, this device measures the upper voltage [24v] and centre tap [12v] and takes power from the upper battery and shares it with the lower battery until they are equal voltages. The advantage of this device, as opposed to a 24-12v reducer is that it is not limited to current. There can be a 100 or 200 amp draw off the 12v battery over a few seconds, even a 500 amp jump start, something that would damage a plain 20 amp reducer [or blow the fuse], and over a few minutes the charge equalizer will slowly top it up again.

What about a plain 24-12v ‘charger’? The problem with that idea is that a charger will provide a constant 14 volts at the centre tap, continuously until the upper battery is flat - it won’t stop when they are both equal voltages as with a charge equalizer.

Scan a vehicle via any diagnostic plug [ adapter bypass ]

There are a large variety of OBD [on board diagnostic] plugs on the various vehicles we may have to work on. The OBD2 connector has become pretty standard, keeping in mind that not every vehicle with that style of plug is OBD2 compliant - there are many vehicles out there with the standard plug that do not communicate using the OBD2 protocols [Japanese pre 2006, Euro pre 2002] but that is admittedly not what we are discussing here.

The fact is that any scan tool you buy will have this plug and the more expensive models will include a set of adapters for the older vehicles. These adapters have no magic bits in them to allow communication with the various vehicles, they are simply two sets of pins internally connected to make sure the correct pins line up on the vehicle you are scanning.

So what happens if you one day find that the vehicle you need to scan does not have a standard plug and you don’t have any adapters to match up with it?

Make your own universal adapter! This is what I had to do when a Polaris Ranger came in to our workshop with a strange diagnostic plug. I was using the budget Autel ML529HD which, on a side note, has gotten into several vehicles that even the factory laptop couldn’t get into.

When you do a search for OBD2 plugs you will find a standard layout for power, ground and the CAN wiring. We are interested in pins 4/5 [ground], 16 [power] 6 [CAN high] and 14 [CAN low]

All you have to do is either buy an OBD plug [link to Aliexpress] or get a used one from an old car. Run wires from the pins mentioned and be ready to connect them to whatever vehicle you need to scan. How will you know where to connect the wires? Obviously ground and positive feeds could go directly to the battery unless you have those feeds available close to where you are working, and CAN high and Low go to their relevant wires, either connected directly to the wire or by pushing wires into the adapter. You could also get a pair of clips to connect to the wires more easily.

And how do you know which are your CAN high and low wires? Measure each of the wires at the diagnostic plug. [article]

If you have an LED test light you will find that the light gives a weak flicker when touched to CAN high and a very weak flicker for CAN low. Simply connect the wire for pin 6 to CAN high and 4 to CAN low. You’ve just created a means to scan any vehicle without having to worry about whether you have the adapter for it or not.

With the particular vehicle I scanned, a Polaris Ranger, the Autel went in via the J1939 protocol and found 6 systems, including electric power steering which is where our fault lay. The advantage with the Autel ML529HD “Heavy Duty” means that it can scan 24v vehicles as well which makes it the perfect partner for a home made adapter, especially for someone doing field work. The J1939 protocol usually accessed around 6-8 systems when connected to a large truck. You could read more about it on my blog for budget scan tools for workshops. When it comes to 12v scan tools my favourite is the Launch CRP123X which I still use regularly for the last 2 years since buying it.

Corrosion protection experiment.

Several years ago while doing work on loaders in an acid plant I did a test with 4 bolts and some wiring connections to see how they would fare mounted behind a cover at the back of a loader.. The end bolt was sprayed with CRC soft seal and wrapped with Denso Tape the next one was sprayed on one side only, then one was only sprayed with Soft Seal while the last was left unprotected. Around 4 months later they were all cleaned off to assess the damage. The bolt with plain Soft Seal came out as good as the one with Denso tape added. This is in an environment that turns a 19mm bolt into a 17mm bolt within a year. Since then I use Soft Seal on anything that will be in a harsh environment.

Honda Accord ABS code 86-01 "F-CAN communication malfunction"

A recent, frustrating job involved tracing a fault code 86-01 “F-CAN communication malfunction” on a 2009 Honda Accord. The short story is that the fault was caused by the YAW rate sensor and the description for the fault code appears to mean “A fault on one of the components connected to the CAN wiring” which is very “general” and misleading.

Initially when the vehicle came in it only had code 86-01 “F-CAN communication malfunction” and a quick Google brought up a troubleshooting page which discusses checking the red and white wires for CAN communication between the ABS module and the ECU, and if they are good “substitute a known good ABS module”. This all suggests it’s all about the communication between the ABS module and the engine ECU.

An oscilloscope was used to check the CAN communication - after first measuring the resistance of the CAN wires at 60 ohms. A “logic” approach was to disconnect both the ABS pump and the ECU while scoping the CAN wiring - this turned the CAN pattern to mush until EITHER the ABS OR the ECU was plugged back in again, then the signal returned to ‘normal’. This proved that there had to be proper contact of the CAN wires at either of the modules.

A “good” used ABS pump was located and fitted and the code returned. Basically the code can be cleared and the ignition cycled as many times as you want and the code doesn’t return until you start the engine. Then one site suggested checking the CAN wiring to the instrument cluster which yielded nothing positive. The place that supplied the ABS pump loaned us the ECU to try as well but the fault just returned.

The next step was to check the live data, maybe that should have been the first step. This was partially informative and confusing at the same time. The steering angle sensor reading showed the correct angle when the steering was turned but underneath that was “Steering angle(CAN)” which showed in the red at 1170 degrees and never changed when the steering wheel was turned. Was this the fault and what was “Steering angle(CAN)”?

The other option was the YAW/Lateral sensor which showed as “normal” when the code was cleared but as soon as the vehicle was started it showed as “failed” and the zero reading changed to a random number. The YAW sensor was under the gear shift lever and the donor vehicle still had its YAW sensor. The “good” used YAW sensor was fitted and this actually fixed the issue of the reading failing when the car was started. BUT: The fault code 86-01 persisted.

The turning point was when someone suggested that maybe that was the whole problem in the first place and the ‘new’ pump had an issue of its own. At this point I remembered that when we fitted the donor ECU it brought up a dozen fault codes for the transmission, because it came from an automatic and this was a standard. There was a difference in the programming of the ABS modules and the ‘new’ pump had an issue with “A fault on one of the components connected to the CAN wiring”. Who knows what it was but fitting the original ABS pump fixed the problem!

The lesson learned was “Before changing components based on a fault code first check all live data” - keeping in mind the fact that live data isn’t always perfect and can still provide misleading information of its own [Steering angle (CAN)].

Fcar F506 24V OBD2 scanner

I recently bought one of these because it advertises the extra features of software for Hino, Fuso, UD and Isuzu trucks, besides the standard OBD2 for cars and diesel OBD. The price was good considering how much professional scan tools cost and it is a welcome addition to the workshop. So far it has managed to get into all the Japanese trucks I have tried it on. Today I had it connected to an Isuzu with a 6HK1 engine. It can scan and clear codes but has no special functions like DPF regeneration etc. All in all it is a nice scan tool for the money and has almost exactly the same interface as our $3000 Fcar, which is handy.

BUT: When you first use it it’s hard not to be annoyed by the main cable which is much too short and looks and feels more like it’s for jump starting trucks its so thick and stiff to work with. It needs to be twice as long and less than half as thick to be more practical. My advice is to get and OBD2 extension cord to make life easier, plug it into the end of the cable and you have something much easier to work with. And the graphing function - I don’t think they did proper testing with that. The first time I tried to graph engine revs it looked like it was working fine, then I gave the engine a rev and the graph shot through the top of the screen and dropped back again at idle. No auto-ranging on a $250 scan tool? A $30 scan tool does a better job with the graphing function.

So would I recommend buying it? Yes, if you work on trucks for a living and charge out scan fees then at $30 a scan this will pay for itself quickly and it’s definitely cheaper than having a $3000 scan tool in each breakdown vehicle. But the Autel ML529HD at less than half the price is also a very useful tool to have on you and does a lot of what the Fcar does - apart from the specialised Japanese software. And the graphing function on the Autel works properly too.

Workshop training manual for apprentices

This is a link to a Pdf of my training manual which I wrote to assist new workers at our auto electrical workshop.

Coronavirus?

Working as an automotive electrician keeps you prepared :)

Audi S6 00288 fault code for the steering lock actuator

Link to my training manual

Someone contacted me about his V10 Audi S6 that had almost $8000 spent on it by the local European car specialists. The main issue was that it would go into ‘limp mode’ or totally shut down with acceleration or deceleration occasionally. First they told him it needed new intake manifolds due to a fault code for the intake manifold runner flap fault codes. $3k later and as he drove away it happened again. They told him “That’s a different fault, we fixed the original fault”. Then it needed two new throttle bodies…. $8k later and several visits with the same reply each time and he wasn’t going to return there. Due to the busy time of the year I loaned him my VAG401 and it cleared the fault perfectly each time it happened.

Part of our conversation went like this:"Basically the steering column lock is making it so the ignition etc is off, so the scanners won't connect"

"The steering column lock actuator module (J518) fails, it's a common Audi A6/S6 etc issue, I've read up on how to disable it permanently but my electrical skills aren't good lol" and he supplied a video link https://www.youtube.com/watch?v=ujxQLU_ ... cODvbuP_ao which shows a procedure for waking the car up after it has died. Turn on park lights, hazards, high beam and press brake, then you can scan it.

Apparently it brought up a 00288 fault code for the steering lock actuator. It never did it for me but the EPC light and traction control light stayed on and though it is a 5.2l V10 quatro, flooring it takes revs to 3000 rpm and it slowly increases speed and battles to get to 60km/hr, it also had a slight misfire.

The codes I had were:

ECU: 5715 "read dtc of ABS"

1431 "thermostat heater control circuit"

6435 "check dtc memory of ECM 2"

ABS: 1826 "SAS voltage supply"

1314 "ECM read dtc"

The customer who had spent months trying to solve the issue provided a link - see #13 https://www.audiworld.com/forums/a6-s6- ... 537/page2/

Also I managed to scan ECM2 and found fault codes for implausible sensor readings from both throttle bodies and cleared them. I then found that if I wriggled the wiring going to the left throttle body the revs suddenly surged and cut back after a few seconds. Since he said it only did it on acceleration it made sense that the twisting of the engine caused the miss-reading at the throttle body sensor when the harness moved and the vehicle shut down because of some sort of logic error. Regardless of the many forums suggesting replacing the steering assembly to fix code 00288 it made more sense that the code was a result of the throttle body fault causing some sort of shut down of the system. This is an oscilloscope pattern of the position sensors on the left throttle body. Two opposing sensors that always add up to the same number so the computer can be sure the signals are ‘normal’. If something goes wrong like perhaps one sensor losing its ground, and it outputs 5v all the time then the two signals added together will go higher than what the computer expects and it will give a fault code, and in this case go into limp mode - possibly also resulting in the steering lock fault

Since the engine misfired when the left wiring harness was moved I removed the left throttle body and gave the pins each a 'twist' to make better contact with the terminals and put it back together, as a test. Lots of test driving later and the problem seemed to be solved. The vehicle was returned to the customer for testing as a more economical option than paying us to drive it till it failed, and it went well for a week before doing it again. The vehicle was brought back in again and the terminals were soldered directly to the pins of the throttle body which fixed the fault permanently. Audis faults aren’t exactly logical - the repair will get very expensive if you replace everything that shows a fault code.

Holden Caprice "pulsing BCM"

The customer complaint was that there was a warning on the display regarding a headlamp leveling malfunction. Sounds simple enough, remove the front bumper, remove the right headlamp and locate the headlamp leveling module. After starting the vehicle up with the headlights on we noticed that every minute or so the headlights went off for half a second then came back on again. We connected the oscilloscope to several of the wires and found that the ignition supply was dying for half a second each time which led to the CAN signal degrading at the headlamp module. Ignition is the red trace, CAN communication in yellow. So the loss of communication is due to the loss in power supply, it’s not a communication issues causing it to turn off.

We also noted that the “ignition circuits 1” relay in the engine compartment fuse box was clicking in unison with the loss of power. A wiring diagram showed that the ignition relay 1 was switched by……. the body control module.

A full system scan showed multiple communication issues between modules. As with all strange electrical issues we first give the vehicle a full system scan, note all the fault codes, clear them, then give it another scan.

Within a few minutes there were fault codes U0140 “lost comm with BCM”in the ECU and ABS modules. Again issues with the body control module.

Fortunately it started faulting more regularly. If it only happened once every few minutes it would have taken a lot longer to trace the fault. There was a purple wire going up the steering column that we had earlier scoped while trying to work out if there was a problem with the ignition supply to everything - we found that even with the ignition off it pulses around once every 5 seconds, then with ignition on it co-jncided with the loss of ignition at the headlamp leveling module. Red is the purple wire, yellow is ignition supply at the headlamp module.

There are a lot of wires and plugs at the body control module which makes for many variables to scope to try to work out why it is switching the ignition supply off. Eventually we found that we could unplug 6 of the 7 plugs and still have pulsing at 3 of the thinner wires. The two wires in the front are permanent feeds, then there are the two black ground wires - they were constant with no interruptions or voltage drops which only leaves the body control module that must have an internal issue.

Worn starter brush prevents starting

This week we had a 1996 Ford Falcon that would battle to start. A garage had changed spark plugs and leads and coil and PC valve while trying to solve the issues. It would take a while to start, if at all, and then run rough for a few seconds then run well after that. We removed the spark plugs and they all looked clean enough, then checked for spark while cranking. There was no spark on any of the leads while cranking but when the key was let go it gave a few sparks as the engine slowed down and stopped. We checked the ignition switch wiring and there was no fault there. [Sometimes the ignition switch can lose contact with main ignition while cranking but regain it when the key is back in the normal position].

The next step was to scope the CAM and crank sensor patterns as that is what the ECU needs to calculate its spark timing. We had found that we could get the car running by ‘flicking’ the ignition switch a few times, the good spark from the ‘off’ time managed to get the car running after a few tries. This is a scope pattern of the CAM [yellow] and crank [red] sensor patterns. In the first part of the pattern the engine is running - then turned off, then the second half is cranking with no-start.

Look at the hash in the crank sensor signal when cranking and then the clean pattern at the end when the ignition switch is let go, and the starter is no longer engaged.

Now look at the battery positive [red] and engine earth[yellow] being scoped while cranking - lots of ‘hash’!

The hash on the crank sensor is directly related to the starter motor - time to pull the starter off and open it up. Look how badly worn the one brush was while the others were the correct length.

A new starter motor was fitted and we scoped the CAM and crank sensor signals again. The first half of the pattern was with the engine running, then shut down halfway through the pattern, and then cranking and starting - it cranked and started good every time after that. The bad brush contact was creating an emp, or many of them as the brush made and lost contact, that was interfering with the CAM and crank sensor signals while cranking so the ECU couldn’t work out the right time to fire the spark. A well programmed computer would be able to work that out and give a fault code - not this one.

24v-12v OBD2 adapter

I’ve been wanting to try this for a while. Quite often I’ve seen Isuzu heavy duty engines listed in the menu of cheap 12v scan tools. Recently my Launch CRP123X showed that it had an update for Isuzu. After it had done the update I had a look and saw options for Isuzu N and F series trucks with 4HK and 6HK engines among others. But since it is only a 12V scan tool that is pretty pointless to have if it can’t be connected to those trucks. I contacted the supplier who confirmed it could not be connected to 24 volt systems.

But since it is only pin 16 which has battery voltage, and the communication voltages are all the same for 12 and 24 volt systems, I ordered a cheap 24-12V converter and wired it up in line with the power supply pins of an OBD plug.

Today I had the chance to test it. A 2010 Isuzu Forward was in our workshop and I plugged in the converter, then plugged in a 24v scan tool to make sure that it confirmed “12v module present” and then plugged in the 12v Launch CRP123X and went into "“Isuzu, 6HK1-Euro 3”. It got into the ECU, read fault codes and showed live data. I just chose barometric pressure sensor voltage and ECU voltage which showed at 24.9v which was the reported ECU voltage, not pin voltage. I tried accessing ABS and SRS but couldn’t get in but am happy to be able to scan the engine computer at least.

Honda Fit/Jazz crank sensor interference

Link to my diagnostic training manual.

We have had several Honda Fits in the workshop for a misfire or rough gear change. They are 4 cylinder vehicles but have 8 coils. A row in front and a row at the back. This is apparently to control “piston slap” so the ECU decides to fire either the front coil or the rear coil depending on engine conditions. Fortunately the first one that came into the workshop actually had a fault code 04-02 for “noise on crank sensor signal”. The crank sensor sits on the right rear of the engine [viewed from the driver’s seat].

Because of the fault code for noise on the crank sensor signal we scoped the crank sensor and one coil and found that the interference coincided with the coils firing. There was also a large voltage drop when the coil fired.

Sometimes a misfire on one of these engines is simply due to the fact that people don’t know they have two rows of coils so they only replace the rear spark plugs with each service. Eventually the spark gap in the front spark plugs wears so large that it causes a misfire.

To solve the problem with voltage drop first, new wiring was run to the coils via a relay. The wires were all run to the centre of the engine [under the manifold] and connected to a relay with a new fuse directly from the battery. This fixed the issue and we thought that was because the voltage drop was sorted out.

When the next vehicle came in with the same issue we decided to do the job ‘more professionally’ and instead of running wires to the centre of the engine the harness was opened up and the relay was wired directly to the original ignition coil wiring. Although this sorted out the voltage drop problem it did not fix the issue of interference in the crank sensor pattern. So the previous job was ‘accidentally fixed’ because the wiring was moved to the centre, not because the voltage drop was sorted out. On several discussions on the topic the initial fix was “replace all 8 coils”. Then someone said “just replace the 4 exhaust coils” [rear coils], finally it was found that simply replacing the no. 1 exhaust coil fixed the problem. Swapping the coils around didn’t fix the problem, all of the coils had reached the stage where they were causing interference but only the one mounted closest to the crank sensor caused an issue.

On one job we tried removing the crank sensor signal wire from the harness and running it along the other side of the engine bay to the ECU. This didn’t fix the issue but when we also took the sensor positive supply and ran it on the other side of the engine bay it fixed the issue.

So the problem is not due to any particular coil or it’s proximity to the crank sensor, it is based on the length of the positive wire that supplies the coil as it runs next to the crank sensor positive feed. The magnetic field that builds up in the wire when the coil fires, possibly the residual energy [the leftover energy that can’t jump the gap after the coil fires] that kicks back to the battery, induces noise in the crank sensor positive feed which interferes with the pattern. The longer wire of coil 1 induces more interference because of the greater length of wire next to the crank sensor supply and when the crank sensor signal gets cut in half to a low enough point that the ECU recognizes it as two pulses the ECU has a problem doing its calculations.

Update: Since writing this post I had another one of these with this fault. The spark plugs were all good so I simply opened up the wiring harness and separated the crank sensor wires for about half a meter and taped them up a few cm away from the coil wiring which fixed the problem.

Here is a photo of the modified wiring. The red section shows the new route of the wiring. The green line shows where it was originally. Tape the wiring up and leave it as far from the main harness as possible.

The Launch CRP123X or CRP123E

The Launch CRP123X is the latest upgrade from the original, highly regarded, CRP123. Some listing for it call it the CRP123E while a listing for the CRP123X states that it is a ‘heavy duty’ version of the “E” model. I’m not sure if there is actually any difference.

The upgrades from the basic CRP123 include a larger screen and body, built in battery, Android operating system wifi connection with automatic update notification. Also included is auto-vin identification that can be turned off in settings if required and a snapshot mode which has a little camera icon on the screen that you tap when you want a picture of the screen, which can then be sent to your email address for printing off a computer. Startup time is about 30 seconds but I no longer shut it down. It loses less than 1% of its battery power each day it is left in standby mode.

Piggy insisted on being present for the video.

Diagnosing battery drain

Before getting involved in tracing where a current draw is, the first thing you need to do is do a full system scan of all the modules and see what codes there are. The vehicle may actually be waiting to tell you where the fault is in a roundabout way. For example a VW with a communication code for the radio would suggest that the radio can no longer get the command to go to sleep, so it stays awake waiting for that command even though the display turns off.

The modules on modern vehicles can take up to 2 hours to go to sleep. If a vehicle has a current draw leave the doors open but latch them [tie a rag around the locator so you don’t slam it by accident] and make sure any door switches are disabled so everything appears to be closed to the modules, do the same with the hood . That way you don’t keep waking the modules up each time you open a door or the hood. Some vehicles will wake up seat modules amongst others when the door is opened, in preparation for someone to get into the vehicle.

Use the oscilloscope to measure the voltage drop across a thin piece of wire in series with the battery and measure the current with a clamp meter so you know what current that voltage represents. A 1 ohm resistor in series with the current draw will give a 1v pattern for each 1 amp of current flow - but for larger current drains this can mean that the voltage may drop too low for modules to operate, and will cause further faults. A roll of thin wire does a better job because even though it creates lower voltages to work with it allows for higher currents before faults are caused.

Set the oscilloscope to a 1 hour, or longer, recording pattern and watch the voltage change while doing something else.

In the following image the red line is 0v while the yellow line shows current draw over time, in this case it was ‘pulsing’ for 5 seconds at a time.

When the fault occurs remove fuses one at a time OR measure the voltage drop across the two contacts of each fuse to see which one has a current draw. If one of them has a current draw there will be a voltage drop across its contacts, that way the modules don’t wake up just because the fuses get plugged back in each time. If several modules are contributing to a current draw do a full system scan to see which ones are still awake. Go through the inputs of each module in live data to see why they are awake. A faulty glovebox switch on a Porsche can make all the seat modules and BCM wake up and stay awake each time a door is opened - because it assumes someone must be in the vehicle if the glovebox is open, so the modules stay awake in case they want to adjust the seat.

Other things to check are current drain through the alternator [leaking diodes] and if there is nothing obvious, the driving habits of the owner. Lots of short trips in winter with the lights and wipers and heater going may drain more from the battery than gets put back in while driving.

The Autel ML529HD obd2 car and truck scanner.

I work daily with various scan tools. Some of them cost thousands of dollars and have some pretty powerful features. But most of the time a simple engine scan is all that is required and since our company has a dozen vans out on the road it wouldn’t be very economical to have a $4000 scan tool in each van. But it also isn’t very efficient when the guys have to drive back to the shop and collect a scan tool each time they are out on a job and realise they will need to scan something, or they are on the other side of town and get sent to a different job that requires a scan tool.

This is where budget scan tools come in, and we have tried various tools and options for an economical solution to the need for everyone to be able to have access to a scan tool in their van. Introducing the Autel ML529HD [Heavy Duty] car and truck scanner.

If you’re in the USA you generally just pick a scan tool that matches the colour of your toolbox and you’re done - because almost everything there from 1996 is OBD2. In many other countries, New Zealand especially, it’s not that simple. We have cars from Japan that are JOBD and only go OBD2 from around 2005, vehicles from Korea are KOBD, several Chinese models, European cars that only go EOBD from 2002, plus all the rest which gets even more complicated in a large auto-electrical company that does trucks and earthmoving equipment as well. Even today, 25/06/2019 I checked the 10 cars that were in our yard for work - only one of them was OBD2, even though they all had the standard OBD plug, only one was OBD2 compatible.

Fortunately as the older cars ‘die off’ everything will be OBD2 and many of our customers are replacing their older trucks with models that are more compatible with budget scan tools - because if you want a tool that does everything we get it costs big money, even then there is no one scan tool that does everything so you need several to cover all your bases. Otherwise, the market is basically ‘growing towards’ total OBD2/EOBD as the older models become scrap metal

Having a 12v budget OBD2 scanner in a van is asking for trouble because one day it is going to accidentally get plugged into a 24v vehicle. I also tried a “V500” HD car and truck scan tool which comes with 6 and 9 pin adapters, and I was assured by the supplier that it would work on 24V vehicles - until it made a horrible ‘ticking’ sound and flashed the screen off and on when I tried it on a 24V truck. I received a 50% refund on that one because it only did half what was advertised - 12v only [it still worked after the 24V incident]

Enter the Autel ML529HD 12 and 24v marvel. It does OBD2, EOBD and J1939 and J1708 on 24V trucks.

What is really interesting about the 24V OBD mode is that it does multiple systems. The Autel MD802 at US$175 is the worlds cheapest full system scanner for 12v only and costs almost double - there’s something about the 24V systems that makes it easy enough to access multiple systems with a budget scanner. The other day we had a 2012 Scania in the workshop and plugged in the $5000 G-scan2 that we had on loan to test. It couldn’t get into the Scania through its model selection or through OBD mode. The Autel ML529HD got into it easily and showed results for multiple systems!

Of course it won’t have bi-directional control and reset functions and advanced graphing features like the serious scan tools do and I wouldn’t take any faults it records as the final say on a matter - even expensive scan tools can sometimes be misleading which is why you always need at least 3 scan tools so that if there is a disagreement between two of them the third can help decide which is wrong. Even then I’ve seen two wrong and one right before.

With regard to the graphing features - it only has the option for one graph which is pretty weak considering something half the price has 4 graphs - but it does the graph well and it moves nice and quickly and smoothly across the screen - unlike the cheaper ones that take 4 minutes to move across the screen and have the patterns all on top of each other.

Then there is the record function - it can either record a series of live data, which plays back in numbers only, not a graph, or you can set it to ‘record on dtc’ which takes a sceenshot of the live data as the fault code is registered. Another nice feature is the green-amber-red lights that show you if there are no fault codes, a pending fault code, or an active fault code. What is really handy about them is that you can be watching a live data graph and see the light change from green to red as a fault code appears, without having to go to the “read codes” menu.

The tool comes with 6/9 adapters for American trucks as well. One word of caution though, I wouldn’t bother trying to update it because the one negative I have seen with Autel scanners is trouble with updates, the language changes to ‘machine code’ or icons disappear etc. I’ve seen it on multiple models. Rather buy another one with the latest updates in 2 years time, they’re cheap enough.

We bought half a dozen of them and in the 3 months they have been in the vans there are good reports coming back, several saying they got into trucks the expensive tools couldn’t do [Including a $4000 Fcar]. Of course we charge for a ‘scan’ and basically 3 scans pays for the tool - after that it’s all profit and convenience. They won’t do everything and occasionally we will want to plug in one or two expensive scan tools to verify the results but so far they haven’t let us down - and of course they work on 12V cars and trucks as well and the tool is the perfect size to have on the seat next to you while doing a test drive and recording a graph of fuel trims or coolant sensor [to look at after you pull over of course]. If you have read this far - all I can say is “just get it!”

Budget scan tool graphing comparison.

I’ve done a video to compare the graphing function of 4 budget scan tools. The Topdon OBDCAN Elite has a very slow moving pattern and the Nexpeak NX501 and Konnwei KW850 are very similar. The Autel ML529HD is the best speed to work with because the other tools move so slowly the patterns are too close together. Though the slower 3 have the advanced ability to graph up to 4 patterns at once it isn’t much use when the screen is just a mess of patterns, so use that function wisely. The main issue with the Autel ML529HD is that it can only show one graph - if they could at least make it two graphs it would be a clear winner because occasionally you will need two graphs. The Foxwell NT630 has good potential because it can show two graphs but the weakness is that they ‘march’ across the screen alternating between graphs - which makes it confusing to work out which happens first. The Foxwell also has a very good feature where there is a greyed out portion that moves quite quickly and after that it slows down and becomes a slower moving ‘stored’ pattern. I got rid of my NT630 for the “marching” issue but otherwise it’s a very good tool for the money. The Autel ML529HD is still the most useful tool on the list so far because it can do 24v vehicles and does several systems.

Budget scantools for workshops

26/11/2018 Under construction with constant updates of new purchases - feel free to add to the discussion in the comments.

If you’re in a hurry for a conclusion then get an Autel 529HD to keep in the breakdown van to get into 12 or 24v vehicles. For the workshop a Launch CRP123X with built in battery and wifi automatic updates for Engine, ABS, Airbag and A/T scanning [the older CRP123 is ls also a solid performer as a cheaper option], an Autel MD802 FULL SYSTEM SCANNER! [or the newer MD805 if you can find one] which also does OBD1 and has proved itself at our worksop, and an Xtool VAG401 for VW, Audi Seat Skoda FULL SYSTEM SCANNER with powerful reset functions at a bargain price. The Foxwell NT650 Eite is also another budget tool at has powerful reset funtions along with injector coding and DPF functions. You could buy all of these tools for 1/4 the price of a professional tool and they will do 95% of the scanning you will ever need to do in a workshop. The other 5% - you will eventually need to buy something ‘decent’ to do reset functions and module linking procedures or outsource to the dealers. But in time the budget scan tools will earn you enough to buy something bigger :)

[For now the Autel 529HD is what we carry in our vans, 12 and 24V and multi systems for the price of a 12v 3 system scanner] Today [18/06/2019] I scanned a 2012 Scania and got all these systems while the $6000 G-scan 2 we have on loan couldn’t get into anything, not even via obd mode.

I’ve gathered together some cheaper scantools to compare in every day use. Keep in mind when reading online reviews of these scan tools the fact that many of the people writing these reviews of products they have purchased have no idea what they are talking/complaining about. Quite often you will read reviews like “Claims it can turn off the check engine light - did not work on my car!” followed by a 1 star rating - well Duh! You can’t just clear a fault code if it is permanent, you need to fix the fault first, only then can you clear the code - maybe the suppliers themselves need to explain this better when they sell the items to avoid confusion though even then many people fiddling with their cars won’t read the instructions anyway. Then I’ve read reviews like “They claim it has bi-direction control over the ABS system but it doesn’t!” - well actually the car you’re using it on probably doesn’t even support bi-direction control even with the factory scan tool - please keep that in mind.

I scan cars every day at work, no one scan tool does the job better on everything than any other one scan tool. each has their strengths and weaknesses. The Autel Maxisys is one of our newest tools and does regular online updates automatically plus multiple functions on a wide variety of cars - but the older Autoland finds modules in Nissans that the Autel can’t, plus it can scan some 24 volt trucks! Then there’s the Fcar that can scan just about any 12v car or 24v truck - but isn’t as good as the Autoland on Nissan cars: My point? Even with high end gear you need several scan tools to cover all your bases - perhaps 99.9% of your bases because there will always be that special function that only the dealers can do - unless of course you spend a few thousand dollars more perhaps - only to find out that the agents in Europe won’t give you the access numbers to recode that module to an Audi with your new scan tool- back to the dealers I suppose. There are some cases actually where you are just better off leaving it to the dealers - like the left read airbag module we got for a BMW - the dealers couldn’t even code it to the vehicle until they worked out that all the other modules on the car needed 10 years worth of software updates approved by the “big guys” in Europe, before they would communicate - something we could never accomplish even with the right tools.

So on to the ‘budget’ scan tools - there are several categories of buyer here:

1.) The once-off purchase by someone wanting to scan their own vehicle/s. It just needs to work for their model

2.) The budding mechanic who wants to try it out on several vehicles and help his friends [for a fee perhaps].

3.) The workshop wanting to have “something for the work vans” that doesn’t cost as much as the professional gear.

4.) Possibly: The new workshop who sees the benefit of buying several budget scan tools that cover just about everything as opposed to spending $4000 a time per professional scan tool that does 95% of what they need - and needing to have one for 12v and one for 24v . There’s always the dealers for the tricky jobs if you’re in a big town/city.

I have researched several models and test them out at work every day to see what they are capable of. In the USA scan tools are advertised as working on vehicles “from 1996 onwards” which is easy enough when obd2 was introduced in that country in 1996 - all you have to have is a scantool that does obd2 and you’re pretty well covered for general repairs. Not so In New Zealand and several other countries where obd2 didn’t come into effect that early. Some countries adopted obd2 as late as 2008 so for many people the other considerations are “Does it do obd1, Australian Ford and Holden, JOBD [Japanese OBD]?” - these are all strong positive additions to the ‘standard OBD2’ that they all cover anyway, and certainly add to the attractiveness of a new scan tool.

Autel: [Reminds me of Microsoft] Our workshop has an Autel Maxisys something-or-other that has a really cool wifi update that just lets you know when updates are available and you download and install them at the tap of an icon. But since the last OS update it occasionally can’t scan a vehicle because it says “diagnostic process already running”. The dealer told me to click on the little car icon and it will be stuck on the last vehicle you worked on and then log out of that. Not so, the only way to get it working again is to do a reboot [like Windows]. The two Autel AL539s we got for our workshop both changed to a weird machine language when we did updates on them and we had to contact the supplier for step by step instructions on getting them back to English.

Someone told me that the AL539B they ordered after reading my blog lost all its icons after its first update. The MD805 multi system scanner I got would get into a Lexus LS430 and tell me what engine it was but go no further. I did an update while waiting for help from the supplier and after that it wouldn’t even log in to the vehicle automatically and ‘LS430’ disappeared from the menu. After a few days back and forth I was instructed to first log in to Asian vehicles, let it do its scan, then go to manual vehicle selection and go to USA models! Well maybe that’s how to get there but with modern technology we’re kinda paying for “the latest” to do that kind of thing for us aren’t we? After all it could find the vehicle on its own before the update [Microsoft]. After all that though I was reasonably impressed that it could do a full system scan and find 26 modules! That’s value for money but ‘like pulling teeth’ to get the job done! [Microsoft] 6/12/2018 I scanned a BMW 750i and found 54 modules with the MD805. I was able to do the whole job on the car with the MD805.

Autel MD805 - notice the reference to the Launch CRP123.

However: The AL539 was an eye opener for me - having mainly scanned for fault codes before and not paying much attention to the I/M readiness [Internal Monitors] function on all the other scan tools this unit has an I/M “hot key” and I now check every vehicle “just because”. The display is really cool and shows everything available [and not available] in “pictures” along with colours that help you see what is and isn’t good - and a green-orange-red display that let’s you know, without even entering into the rest of the ECU, whether things are good, suspect, or bad in the system! What first struck me was the fact that I/M readiness showed that HRT [heated oxygen sensor] was not good on a Lexus I was working on. I checked live data and there was no activity at the oxygen sensor and obviously zero short term fuel trims because it had nothing to work from. These ecus don’t throw a code for a faulty oxygen sensor strangely enough. I wouldn’t have known if I had simply scanned for fault codes. Then, while I was watching the display of the I/M I saw a pending fault code appear for a valve that wasn’t connected [had been removed] and after 30 seconds I saw “2” appear under dtc. [diagnostic trouble codes] - all things that I would have had to re-enter the ECU and scan again using a bigger scan tool. Since the check engine light wasn’t coming on right away as well these things were all so handy to have just “popping up” while watching the I/M display. [The two fault codes were for VVT control because someone put the engine back together without checking cam timing correctly]. I may be going on a bit here but “a picture says a thousand words” and it is really refreshing having a colourful representation of what is going on compared to the boring “government hospital” layout of most I/M readiness displays on other scan tools. Autel official store

Foxwell [reminds me of Apple products, BUT at a reasonable price!]. Solidly built, reliable, does what it’s made for well and at a good price! I bought an NT630 Elite after trying out a friend’s model. Powerful little tool indeed! The Lexus I was working on ran the battery flat while trying to get the Autel MD805 to scan it -grrr! When I went for a test drive after jump starting it the traction control light was on. I scanned the ABS system with the Foxwell and it told me the module had “lost zero point calibration”. I went another step and found “test mode”. After running test mode the traction control light was off and we were good to go! Supports AU Ford after 2003.

Foxwell NT630 - notice the reference image showing “others” which is an image of a Launch CRP123.

Now is a good time to discuss the Launch CRP123. It’s really the benchmark of budget scan tools. As can be seen in the last two images when you start reviewing the better budget scan tools you will often see the CRP123 mentioned along with statements as to what else the advertised tool does beyond what the CRP123 does - never any statements like “does better than” or “more reliable than” because the launch really does its job well, and covers a wide variety of vehicles. The Foxwell adds SAS and ABS reset modes beyond the CRP123’s capabilities but doesn’t cover things like AU Ford and JOBD. My advice is to go for the higher level CRP129 which does have those functions - at twice the price of the Foxwell NT630 mind you, but also does automatic transmissions. The Launch can also display 4 graph data streams while the Foxwell can only do 2 at a time. Not a dealbreaker for me because 2 graphs is enough for most jobs and beyond that the screen just gets messy. I eventually sold my CRP123 and bought the higher specced CRP129 for only $10 more when the price dropped to the level I was waiting for. 12/05/2019 I sold my CRP129 due to lack of use. Besides the fact that we have several large scan tools I find I prefer the one handed grip of the thinner scan tools while doing test drives.

If I were buying my first budget scan tool I would start with the launch crp129. However, as per my update regarding selling it I have found that I always grab the scantool that can be held in one hand when working on cars and doing test drives. Not that I stare at the screen while driving though but something like the Nexpeak NX501 is so much easier to work with if I pull over to the side of the road.

Launch has always meant reliability for me - until I ordered the new CR3008 that arrived a week ago. It scanned half the vehicles I tried it on though admittedly New Zealand gets quite a selection of vehicles, many of which aren’t obd2 compliant. But most of the vehicles it couldn’t scan the Foxwell Nt630 could, as could the Launch Creader VI+, so it should have done better. At first I thought it was because the one corner pin was shorter than all the others but the supplier assured me it as “Launch design” and I worked out that it was the B+ terminal so if the tool was turning on then it must have been making good contact. I soon lost confidence in the tool, got a 50% refund on my purchase and got the other 50% back by selling it at a good price. If Launch want to bring out a “new release” it should a least be able to keep up with the old models.

Today, 14/12/2018 my Nexas NL102Plus arrived and first thing I did was plug it into my 2006 Honda Stream. It was able to scan it and get graphic live data which is already better than the launch 3008 I got rid of. In New Zealand not everything is obd2. compliant so many of the cars like my Honda that come from Japan as used cars can be tricky to scan with budget tools. This scan tool has me very excited because it is 12 and 24v and does several systems. It also supports oil light reset and DPF regeneration. On Monday when I’m back at work it is going to get a full test! Update: We kept one of these for our heavy mechanical worksop and I sold my own personal unit - a single graph in live data option is a bit outdated for me, and I wasn’t able to do a dpf burn on any if the Isuzu trucks I tried it on.

17/12/2018 Today I listed 10 vehicles in our workshop: Japanese vehicles pre obd2: 1998 Toyota Harrier, 1995 Rav4, 2007 Toyota Dyna, 2004 Honda Odyssey, 2002 MMC Smart K, 2001 Toyota Hilux, 2006 Toyota Auris. Then there was the 2000 Ford Falcon which is “AU Ford”, a 1988 BMW 320i and finally a 2015 Jeep Cherokee which was the only obd2 vehicle out of the 10. The others had obd plugs but they were obd1. The Japanese imports were all pre 2008 meaning they had not gone full obd2 yet. That’s what we have to deal with. In the USA one obd2 scan tool would have been able to scan 9 of the vehicles because over there everything after 1996 has to be obd2.

21/12/2018 My Nexpeak NX501 arrived. It is a well made tool and so far the best ‘feel’ when the buttons are pressed. The “mode 6” or “I/M readiness” display is nice and ‘graphic’ as with the Autel Al539 compared to the boring numerical display of most other scan tools. I asked them about the fact that some pictures show the front with text saying “obd2 and obd1” but they tell me they are now only “full obd2”. For the price also having obd1 would have made it an exceptional bargain.

I was keen to see if it could print graphs as the listing suggested on Aliexpress. Not so.

I contacted them about the misleading nature of this image - it shows a graph being printed and I can imagine that being a hit with customers - “a picture says a thousand words” as opposed to a list of numbers you have to decipher. It would be really cool to be able to show the customer something like changing fuel trims compared to engine revs and I’m pretty sure they would be impressed and gain more confidence in our abilities. I did everything I could to try to print out a graph and then contacted support who told me it is not possible - the “media department is responsible for the pictures in the listing” and they thought they were being clever by showing a graph being printed.

I gave them a 3/5 star rating for “item as described” but 5/5 for service and didn’t request any compensation - I just expressed my disappointment in it’s inability to do what had caught my eye in the listing and they have “promised” to change the offending image - after all it certainly suggests you can print graphs.

All of that aside it is already one of my favourites now - the graphic I/M readiness display, the green-orange-red lights showing “pass” pending code” and “fault code” on the front which means not even having to scan the vehicle again to find out that a code has appeared and the superb feel of the buttons. Whenever I think of buttons on these scan tools I think of the awful squishy buttons on the Launch Creader VI+ which require what feels like twice the movement of squishyness of other tools to be pressed down before you have to push harder to get a ‘click’ - if it wasn’t for the fact that all of the buttons feel the same I would have concluded that something was broken on my Launch Creader. This also reminds me of how dark the Creader display is - I dug into the menu to see if there was a setting for brightness but there isn’t. But I digress - I wish all my scan tools had the same feel as the buttons on my NX501.

Speaking of buttons - most of these tools have a “shutter delay”. I’m now comparing them to budget digital cameras where you aim at the subject, push the button, and then the subject steps out of the way just before the shutter finally goes “click” and takes a picture of …. nothing. The Autel and Foxwell come to mind right away, you want to scroll down the screen and click the button several times and there is such a lag you end up going one or two lines lower than you wanted. You have to either click slowly and wait or count the exact number of clicks required and push the button that many times then wait - which is a rather ‘disconnected’ way of working with the tool. The Nexpeak has a fast enough response that it doesn’t leave you wondering if you just pressed the button and it’s about to move down a line or not. The ‘beep’ is also pleasant enough that I didn’t bother about going into settings to disable it as with most of the other tools that are loud enough to be heard in a noisy workshop - meaning that when the shop isn’t noisy the beep is just plain annoying.

Graphs: The Nexpeak 501 is the clear winner here, up to 4 graphs at once “moving smoothly” across the screen. The Autel 805 can show two graphs, one above the other, or “merge” the two but they are still jumpy and out of phase so if you are watching short term fuel trim and oxygen sensor readings at the same time they take turns at refreshing which is annoying. The Foxwell has quite a nice display of the graph [two only] but the lag on its buttons really annoys me - you have to wait a while between clicks to see where the cursor lands. When I’m using the Nexpeak I don’t even think about any of these issues, when I pick up the other scan tools I immediately start thinking of how I have to work around their limitations. The Autel MD805 is not bad on the graphs, the refresh rate is reasonably fast so that when you’re viewing two screens, one above the other [there is also an option to merge the graphs as well], it’s not as irritating as the Foxwell NT630 which “marches” the screens, left right left right left right…. and makes it hard to follow because your concentration goes up down up down up down…..

8/1/2019 Today we had a 2002 Holden VX in the workshop. The Autel MD805 was the only one that would communicate with it. The Launch CRP123 only goes back as far as 2005 on Holdens.

With regard to “button lag” the reason why the Nexpeak is the smoothest to work with is because it only acknowledges a button press once it has moved to the next line from the previous button press. In other words you could press it 5 times very fast but it will beep once and when it has moved to the next line it will accept another press[presses] to move to the following line - which makes it easier to get where you want to go without ‘overshoot’. The other tools will give you 5 beeps if you press it rapidly 5 times and then eventually get 5 lines down - which results in a lot of overshooting the target because you keep pressing the button to get lower down the screen because of the slow response time.

At the moment, if I had to choose only one budget scan tool it would be the Autel MD805 because of the wide range it covers and its ability to scan 54 systems. If I was only working on engine faults and every vehicle was 0bd2 in our workshop [highly unlikely in the New Zealand vehicle environment] I would take the Nexpeak NX501. It’s smooth operation, graphic I/M readiness mode and smooth moving 4 graph screen are the winners in the budget scan tools department.

20/01/2019 Today I used the Autel AL 539 multi-meter function and for no real reason clicked on “review data” first to see what saved info looked like from my last obd2 scan. The menu flashed quickly and switched to Spanish or some other language - I double checked my settings and it is set to English which of course is what the main menu showed anyway. Autel products seem to be fraught with bugs.

30/04/2019 - my Autel ML529HD arrived and so far I am reasonably impressed with it. The buttons are a huge improvement over the older Autel scan tools’ “clicky” buttons. The first thing I tried it on was a 2010 Volvo truck fully expecting that it would not work because many of these 24V compatible budget scanners are only good for American trucks with their 6/9 pin configurations. It actually got into the engine ECU and exhaust after-treatment systems, found the fault codes and provided live data. Time will tell if it can get into the Japanese Isuzu trucks we see so often and I will update once I know.

18/05/2019 Someone contacted me and expressed concern that the instructions that came with his ML529HD stated that the operating voltage was 9-16v. Mine works fine with 24v trucks and this is from the site I bought it from, stating that it is good for 28v.

6/05/2019. It couldn’t access a 2007 Isuzu through a 20 pin adapter but it got into a 2011 Isuzu easily and gave fault codes and showed live data. 9/05/2019 Scanned a 2005 Nissan UD truck with it. 20/05/2019 Received confirmation that it can scan a 2019 Hino and get into ECU, A/T and Allison auto shifter, also scanned a 2013 DAF with it.

22/06/2020 and the ML529HD is still showing up more expensive scan tools. It got into a Terex ‘bobcat’ that the dealers couldn’t scan, and neither could our $10 000 Jaltest ‘super scan tool’. It got right in and gave a fault code for the EGR valve after a technician had spent several hours with various scan tools and laptops trying to access the ECU. I’m not saying this will always be the case but for the price it is definitely worth having around!

Then I thought I had found what I was looking for, the “V500” whatever brand that may be. At a little over US$82 it is advertised as being for cars and “Heavy duty” trucks including…. wait for it….. Hino and Isuzu! AND!!!!! a dpf regeneration function! It sounded too good to be true and when I looked through the specs I saw the rated voltage was 9-16v hmmmmm?!. I contacted the seller and asked about this and was told “It can do 24v trucks as well, I will change the specs!”. Exciting stuff, one of the cheapest scan tools and it advertised that it could do essentially what we need most in New Zealand. Today it arrived, 06/05/2019, I tried it on a 12v Mazda and it worked good and a few minutes later a 2011 Isuzu drove in needing a dpf regeneration - perfect! Alas, the screen just ‘ticked’ as it made small ‘flashes’ on the edges because it couldn’t handle 24v. I’ll be getting a refund on this one. When I plugged it back into the Mazda it worked again which is a good sign that there is no permanent damage and it is probably still good for 12v but it appears that “heavy duty” means American trucks which are mostly 12v and possibly they have 12v Hino and Isuzu trucks over there - I suppose one day they will realize that 24v is more suitable for trucks, perhaps when they go metric…. Yeah right! The plug was also VERY tight so even if it is good for 12v trucks it is not a tool I would recommend.

Update: 22/06/2020 I just received another one of these because they were advertised as 9-30v compatible at a good price and I wanted to see if either they had been upgraded or perhaps I just received a bad copy the first time. This time it is working fine on 24v UNTIL I start the engine and it starts charging at 28v. Obviously they haven’t fixed the problem..

Then there’s the budget-squared [budget budget] scan tool. The Launch CR3001 is a tiny scantool that is ideal for keeping in the glove-box of your car, for around US$15 why not keep a spare. I think the picture they display bragging about the strength of the cord was taken when the user tried to strangle it in frustration while waiting for results. But then having to wait twice as long to get codes is still worth it compared to having to drive to a workshop and pay for a scan, even if it’s just for the peace of mind of knowing that the fault is not serious enough to warrant cancelling your vacation.

18/05/2019 I just checked my list of orders and I now have 9 budget scan tools on their way from Aliexpess - I have found that they sell pretty easily for slightly more than I pay for them and since I wait for the best prices before buying this is still quite often less than what people would pay for them if they tried to buy it themselves. It’s a win-win situation, I get to try them out, keep the ones I like and sell a “tested” model to someone else who doesn’t have to wait 3 weeks for it to arrive.

The Topdon OBDCAN Elite is quite a handy little tool, small and easy to handle with a reasonably large screen and 4 graph display. My main gripe being that the up-down buttons require a little getting used to but after a few minutes it’s not so bad - but could be better. For around US$70 it also does ABS and SRS which makes it one of the best value for money tools. Along with that it comes with a pretty professional semi-hard case and nicely printed manual which already makes it a step above most other budget scan tools. When you first open it you see a snug fitting foam cutout holding it in place with the cord neatly tucked in behind it and straight away you think “that’s the last time it will be like that!” because there is no way I’m going to have time to tie it all up so neatly each time - the foam goes in the bin and it all gets forced back in each time and then the case seems to be a little shorter than it could be. Besides the solid structure of the case it also has an internal ‘bookmark’ flap that folds over the screen and protects it nicely from sharp edges in the accessories pouch. Topdon is certainly a class above the rest in this regard.

The first thing I check with any scan tool is the graphic display, after all, besides scanning for codes, this is where we do our diagnostics. The Foxwell and Autel models have a pretty nice movement to their displays, meaning they go the right speed to show the information. The Foxell has a greyed [blued] out portion where the graph moves pretty quickly before hitting the other 80% of the screen where it slows down considerably. The faster moving portion is very useful in many situations. The Topdon and Nexpeak simply “slow down considerably” from the beginning which can be way too slow to check something like O2 sensor and fuel trims. I timed this screen at about 2 minutes to reach the centre point.

A lot can happen in 2 minutes of the engine running especially if you’re watching both O2 sensors and short term fuel trims on one screen. This results in a mess of coloured zig-zags on the screen which is almost useless. Of course most of the time we only need to see one or two graphs and if we add information wisely then something like engine coolant temp won’t create much mess on the display, and quite often a quick rev of the engine gets the auto-ranging of the display to separate the patterns to a degree, which I observed while viewing 4 patterns at one stage. They were all just a mess on top of each other but a rev of the engine separated them into something legible.

Besides the small gripes this tool is well worth it at about 1/50th the price of a professional tool and it worked well on my 2004 Honda Stream. When I was going through the various brands in the “scan” section for ABS and SRS I did see Holden in there which is always a bonus for those of us ‘down under’

Konnwei KW850 US$50 and a really nice tool for that price and a decent length cord compared to most budget scan tools. I plugged it into the 2004 Honda Stream and had a look at the graphing function first. The fact that it has the ability to do 4 graphs is nice to know but of course you have to be prepared for the patterns to interfere with each other a bit. The graphs are almost as slow as the Topdon and though it would be really handy to be able to adjust the refresh rate of the graphing function it is a bit much to ask of such a reasonably priced tool. I had to go back to the tool and press the buttons a few times to be able to comment on them because initially when using it I didn’t even notice what it was like - which is a good thing, it means they weren’t irritating. The buttons are on a par with the Nexpeak meaning they feel really good when operated.

The front says it does OBD 2 & 1 but I’ll need to ty it out first to believe that. Several pictures I’ve seen of various scan tools mention doing OBD1 as well and when I ask about it I get told “They used to do OBD1 now we concentrate on OBD2”, but they forget to remove “OBD1” from the case of the tool.

24/05/2019 and the launch CR 6011 has arrived. launch is a pretty trustworthy name and I’ve never had updating problems with any of their tools. I liked the look of the long screen but am amazed that they didn’t use that extra space to place graphs one above the other. It is capable of 4 graphs at once, in colour, and once again if you use all 4 the screen becomes a mess. besides that it’s a very solid feeling tool and the buttons are very solid, almost to the point of being stiff, but nothing to actually complain about. The 6011 does ABS and airbags as well for around US$95 which is still a good deal.

Though it has a dedicated I'/M readiness button the display is nothing to write home about - just rows of numbers that makes you think a bit harder then the colourful I/M display of some of the cheaper models. If I’m only scanning an engine ECU I will be reaching for the Nexpeak NX501 for the better user experience. However this tool is a bit more professional in that it can also do ABS and SRS while the ‘user experience’ aspect of my choice is based on personal opinion regarding the buttons and general feel of it.

Also does Ford and Holden.

The Nexas NL101 is a handy size scantool with well laid out buttons ….. when it actually works properly. I plugged it in to my 2004 Honda Stream and it worked ok once, then a graph of the MAP sensor froze and the ‘esc’ button did nothing to reset it so I had to unplug it to start over. Then it got stuck on “iso9141 “which is what my car works on and after 2 minutes of looking at the screen and pressing the ‘esc’ button I had to unplug it again to start over. Then it got in to the ECU again and showed a good STFT graph and when it was changed to ECT it worked for 5 seconds and froze again. This one will be going back for a refund.

The Autel ML629 is a slight step above the others for US$100, besides engine, ABS and SRS it also does A/T. What is especially nice about it is the graphing function, though it is limited to two graphs [usually enough for most diagnostics] it has the option to show the graphs separate from each other or merged. It also has a ‘pause’ option which means you don’t have to slam on brakes and veer off the road when you want to take a photo of the evidence, you can do it safely by pausing the screen until you have a safe spot to stop. On top of all of that the graph has two sections, fast moving and slow moving. Most budget scan tools only show slow moving combined graphs meaning the pattern can get messy and confusing over the 4 minutes or so it takes for the screen to move from one side to the other. This tool shows the pattern moving fairly quickly over the first quarter of the display then it slows down to ‘storage mode’

19/12/2019 Update. I bought another Autel MD805 and did updates on it when it arrived. The updates went ok but all the icons have turned black whereas they used to be different colours which makes it harder to find what you’re looking for. Then I dug out the Autel MD802 we bought a year ago for the workshop and did updates on it. For some reason the anti-virus kept raising issues and now the tool no longer turns on if the SD card is inserted. I’m still waiting for support to tell me how to fix it. Only update Sutel products if you absolutely have to.

Diagnostics using fuel trims

This is something I need to improve on since it can save a lot of time working in the wrong direction if you know how to read the clues. For now I will simply gather information and start trying to apply it.

Fuel trim data for diagnosing

Vacuum leak at idle

Here’s a photo showing oxygen sensor vs fuel trim adjustments.

Budget obd2 Scanners

As an automotive electrician I am always on the lookout for well priced scan tools. The company I work for P&B auto electrical, has several [expensive] scan tools each of which has its strengths and weaknesses. The Autoland is really good on Nissans and often the first tool that I grab because it generally gets into any vehicle without asking multiple questions like the old but very reliable Snap-on Solus does. One problem with the Autoland is that it can be too keen to get in automatically and on some Holdens it will think it has found the right module but ends up giving 7 fault codes for the airbag system when in fact there is only one. But among all our scan tools it is without doubt the best on Nissans and was recently the only one of 5 scan tools that found the “hood pop up” module on a newer Nissan when a full system scan was conducted. This module has nothing to do with the hood being open, it connects to several “pedestrian detector” sensors in the front bumper so that if you hit someone it can ignite the hood release and provide a soft landing. I have a lot of respect for the Autoland and when my budget Autel MD805 full system scanner arrives I hope to test it on a Nissan and see if it can find that pop-up module. [I don’t get commission from Aliexpress - they just provide so many good deals!]

Autoland

The Snap-on Solus is our oldest scan tool at work, I use it when I need reliability but don’t enjoy the “20 questions” it asks before it will access a vehicle, or the fact that many of its adapters require a special key to be inserted for each vehicle. But the fact is it has never let me down and is the best tool for Mercedes Sprinters [it finds features other scan tools don’t for Sprinters].

Snap-on Solus

The Autel Maxisys pro is our newest scan tool, it’s really good the way it stays connected to wifi and lets you know when it has updates - though it’s quite expensive to subscribe to constant updates - for the NZ$1200 a year we could just buy a new scan tool of another brand with the latest updates each year. Because it’s a tablet it also has the weakness of being as reliable as a computer.

Autel Maxisys

Then there’s the 15 year old Launch X431 Diagun, very reliable and sometimes surprises with functions the bigger scan tools don’t have, good with European vehicles - we leave an extension lead on the bluetooth adapter so it’s not that easy to forget in cars.

The Fcar is the best on trucks, slightly strange software to work with compared to the others so I haven’t used it much on cars. Made to military specs the boss almost freaked when the sales rep threw it onto the concrete floor to demonstrate its strength, then picked it up, rebooted and carried on scanning a vehicle. This is the only kit that came with a 12 pin Isuzu plug that we needed on a recent job to perform a dpf regeneration.

The old Tech2 is like the dinosaur of the bunch but very good for its applications.

So, on to “budget” scan tools since we’re all after a bargain and after all, why pay more than you need to if you can do the same job for less? First there is manual code extraction with detailed instructions on rennacs showing which pins to bridge out to extract codes manually.

For phone based bluetooth scanners the ELM327 is the cheapest and most popular option starting from about $2 for possibly a rip off of the original. Good if it does what you want on your own vehicle but nothing I would want to seriously work with. Considering the price there’s no harm in keeping one spare in your tool case, or glovebox, for the chance that it could save the day in an emergency..

ELM327

Then there’s the Xtuner CVD16 heavy duty option that does 12 and 24v vehicles - which would be great if it worked on everything I’ve tried it on but doesn’t seem to be able to get into the Isuzu trucks, though it got into a Chinese Foton truck ok. It has a nice recorder-graphing function that allowed me to record the engine revs vs air flow sensor readings while driving a VW Touareg and then view it later in playback mode. Worth having in your kit for the price.

Xtuner CVD16

A work associate recently bought a Foxwell AL630 Elite and left it with me for two weeks and it got into every vehicle I tried it on except an “older” 2006 Toyota - I think they only went full obd2 after 2008 and not many budget scan tools can access the older Toyota ECUs [the CRP123 can’t either]. I’m hoping the Autel MD805 will do that for me - will update after it arrives. This little scan tool looks very promising especially since it can also do SAS [steering angle sensor] resets on the relevant vehicles. I have a feeling that to do the older Japanese imports that we see in New Zealand a scan tool that advertises “JOBD” is what is required [Japanese OBD]

Foxwell NT630 Elite

I also have a Launch CRP123 which I bought after much research, a very capable little tool which can also get into A/T [automatic transmission] modules [along with engine, airbag and ABS] which the above Foxwell can’t. But then it can’t do a SAS reset. Every year these tools get better and cheaper so there’s no reason why the average ‘tinkerer’ can’t afford to have something to dig deeper into their vehicles systems and save themselves lots of headaches [or possibly cause some if they don’t diagnose properly but that’s another story]. The Launch CRP129 specs appear to be a combination of the two tools, the CRP123 and the Foxwell NT630 Elite, because besides scanning the 4 main systems it also advertises the ability to reset systems like ABS and steering angle sensor.

Launch CRP123

Then there’s the “must have” Autel AL539 multi-meter/scanner. Get it for the multi-meter function and you have a bonus of it being a backup scanner - and it has a built in battery [I wish our $3000 Autoland had one]. Since it has a dedicated I/M readiness button that is a feature I am learning to use as well but the fact that it has an a/c voltage display means you can actually use it as a basic oscilloscope. The obd2 function is all you get as a scan tool but the other day after diagnosing a fault on a Lexus with the expensive gear I scanned the same vehicle with this tool, got the same VVT solenoid fault codes as the $4000 Autel and moved the $8000 oscilloscope out of the way and connected the two leads to the VVT solenoid and it auto-ranged the PWM signal and showed me the pattern and told me it was a 22% duty cycle - everything that $1200 worth of ‘other’ gear had done. Obviously it doesn’t have the same depth of functions that “the good stuff” has when you have to dig deeper but for 90% of the diagnostics we do it was enough. It also has some interesting functions like checking charging via the obd plug and checking battery voltage when cranking which basically measures the minimum voltage the battery drops to when you start the vehicle. Apparently the AL539”b” has a ‘proper’ battery test function as well. Just a warning, when you update it suddenly the display changes to numbers you can’t interpret and you have to reset the language to English to use it again. This is the reply I received from the supplier to navigate the menu again.

“Hello Just checked. Because you chose wrong language. Please follow the steps below. 1. Choose ff 00 00 01 00 09 2. Then choose ff 00 00 01 00 68 3. Then choose any code. 4. It will show languages options, please choose the language you want. Note: If there is no ff 00 00 01 00 68 in the second step, please try three options to find the languages setting page. Thanks.”

After posting this blog a reader bought the “b” version and made contact to let me know that their unit lost all its information icons on the menu, though it retained the text, after his first update. One would think that a company that sells so many promising products could get the updating process right - at the moment I favour the Foxwell quality and update functionality.

Autel AL539

For budget car and truck scanners the Multidiag pro+ is a useful tool that can either plug directly into your laptop or you can get the newer bluetooth version. It has quite a comprehensive list of vehicles that it scans along with a “Trailer” option for Wabco, Knorr and Haldex ABS. I have used the older “USB direct connection” model connected to our workshops’ windows 10 laptop with success, but the “new improved” bluetooth model I bought for my own windows 10 laptop gave a lot of trouble trying to set up because it isn’t written for Windows 10 [stated as “windows XP or Windows 7 32 bit] - and when I installed the drivers manually as advised it interfered with my trackpad and keyboard, so I had to reset my computer and remove the software. It also comes with a disc for the software along with a “keygen” which you have to run to activate it, suggesting that it isn’t exactly a legal way to do it. Then you have to turn off wifi before opening the program so it doesn’t go online and tell you the program needs to be activated - all to much hassle for the average user.

Multidiag pro+

Finally [for now] there’s the Autel MD805 which is to date the cheapest full system scanner which ALSO does obd1, besides the standard obd2 that every cheap tool does anyway. This is useful for people in a workshop who don’t know what vehicle they will get next. If it’s your own vehicle and you don’t work on anything else then get whatever does the job but if you want to be more versatile then get something that does "pre-obd2” vehicles as well. After a bit of research, I had initially thought that the MD801 and MD802 which advertise “pre obd2 vehicles” on their hard case were the only ones that did OBD1 as well, because the MD805 didn’t actually mention “pre obd2”. But when you look harder at the description on the MD805 they mention that it also does the same vehicles as the MD701/2/3/4 which are “pre obd2”. I will test it extensively when it arrives because if it actually does obd1 and obd2 4 systems plus “50 other systems” then at the price there won’t be much point buying any other scan tools in the price range [besides having some sort of “double check” option if the code you get seems weird, it’s always good to have some option to confirm it] The Foxwell NT414 4 system scanner seems to be the only other tool in the price range [90% of the price] that also does obd1 - it doesn’t do a full system scan though which is pretty essential these days in a scan tool so it’s well worth paying another $20 for the MD805.

Autel MD805

That’s it for now up to 11/11 2018. I will update this blog with my findings on what these budget tools can and can’t do.

15/11/2018 The MD805 arrived yesterday and has done pretty well on each vehicle I have tested it on. Except the 2005 Toyota Camry. It does an auto search, finds the vehicle, tells me what model it is and what engine it has but goes no further - no matter what I press it doesn’t scan anything on the vehicle. I’m still waiting for feedback from the suppliers on what I’m doing wrong [or what the tool can’t do that they advertise it can do]. Besides that, I would still buy it again given the chance. I just got back from a test drive in a 2013 Ford Ranger where I graphed the wheel speed sensors in the ABS module. It can only merge two graphs at a time, even if you select all 4 wheel speed sensors it will graph the first two - then you have to select the other two later and check them separately.

23/11/2018.

My Foxwell NT630 Elite arrived this morning - I have had the chance to test a work associate’s unit for a few weeks and I’m still impressed with this unit. I had connected the Autel MD805 multi system scanner to the Lexus LS430 I’m working on and all it could do was scan obd2 fault codes. When I tried to access ABS it goes through the motions and leads me to the “Lexus” icon and even tries to access the vehicle and actually tells me its model and engine type. Then there’s this awkward silence as I press the “ok” button multiple times and nothing happens - I’m still waiting for Autel support to get back to me on this one. I plug the Foxwell NT630 in and there is an ABS option right on the screen which took me into the ABS module, scanned it and told me that the “zero point calibration” had been lost. I found a “test” mode and it reset it for me and the light went off! I tried with the Launch CRP123 and it could read the codes but couldn’t do any special functions - I imagine that is what the CRP129 for another $50 is all about.

Though I had trouble updating the Autel AL539 and so did someone else who read this blog I am still finding it to be my favourite tool at the moment. The I/M readiness mode is so cool the way I can tell what the engine isn’t happy with and while I had the Lexus engine running I can watch that screen and see the “pending” fault codes pop up a “1” as the ECU picks up that the VSV solenoid is open circuit, then 30 seconds of idling later I see a “2” pop up under the current fault codes area when the two VVT solenoids aren’t getting the desired response from the ECU.

With regard to the update issues of the Autel AL539, two of us at our workshop ordered one. I updated both of them as soon as they arrived and their menus both turned to numbers instead of words. The supplier gave me the sequence of numbers to select to change the “language” back to English. Then someone on the scannerdanner website read my comments about the AL539 and bought himself the AL539B with built in battery tester and reported that when he did the update all the icons on his menu disappeared. I think Autel needs to re-think their program somehow and provide a more reliable update system because they will be left behind by products like Foxwell and Launch who have so far provided flawless updates in my experience, an work well - unlike the Autel MD805 that hits a roadblock when I try to scan a 2000 Lexus [video].