WG Jeep Geek - Tinkering with Jeep Electronics
 

I've posted a few things in the "What did you do to your Grand Today" thread that seems to have prompted a bit of interest. Hence, as requested, I am going to attempt to document some of my work in a bit more detail to help others.

A bit about me...
I'm a '60's child, married, two kids (one adult and the other soon to be) and hold a senior position as a professional expert in the mining industry. In my youth, I raced off-road. I used to have a wall full of trophies. Now I have a box full somewhere in the garage, if only I could find it.

Fifteen years ago, two friends and I set up a boutique electronics company as a paying hobby. My job was to program the Atmel AVR chips (this was long before Arduino existed). I also had a lot of exposure to circuit design and construction, so I am pretty handy with a soldering iron. I also built my own PVR (personal video recorder) for the challenge. Sounds impressive? It's really just a computer running MythTV software and a gazillion TV tuners hanging off it.

I purchased my 2004 2.7CRD WG in May 2017 after quite a bit of searching for a low-cost but capable 4WD. She has a few issues, but in terms of comfort and capability, I think I hit the jackpot. My soon-to-be-adult son enjoys going 4WD-ing with a few blokes from church once a month of so. Nothing too extreme, just explore, have fun, fish, swim, get stuck, snatch out, and then come home and fix the things we broke. The blokes have given me the CB call-sign of "Cheap Jeep." I don't mind, because they also know that I'll try stuff they won't - mostly because, as one said, "If he breaks it, at least he knows how to fix it."

Enough about me. This is already getting into TLDR territory!

This is my first "How TO" so please be gentle with the comments. More topics will follow, I hope, including more details on fixing the electroluminescent lighting in the WG gear changer for around $5 - without grafting in LED's.

Overhauling the Transmission Control Unit

First, a special shout to Kaido at www.jeepswj.com. I emailed him asking about his replacement PCB. He asked me about the error codes, then informed my NOT to buy one from him but instead to replace the transfer case switch. I recommend his fault code software, but please donate to support his work.

Many of the pictures below are linked from jeepswj.com. I trust he does not object.

Step 1 - Remove the console:

Undo the six screws:
http://www.jeepswj.com/wp-content/up...ee-console.jpg

Take care to get the correct screws! The two on the right below are hidden by the rear cup holder, if you have one. Open the cup holder to find them:
http://www.jeepswj.com/wp-content/up...er-console.jpg

Step 2 - Remove the TCU:

If you have not yet done so, now would be a great time to disconnect your battery. Did I leave that part out? It does not matter... until now. Disconnect the battery NOW.

The TCU lives under the console. On RHD vehicles, it would be right by the driver's left calf:
http://www.ausjeepoffroad.com/forum/...1&d=1503656349

Simply unplug the cable (you HAVE disconnected the battery, right?) and remove it. Mine was held in place by a single zip-tie (aka cable tie). Just cut the cable tie.

Step 3 - Dismantle the TCU:

The PCB is held in by four clips, marked red below. I ended up borrowing 4 knives from the kitchen to simultaneously pry all four clips to allow the PCB to pop out. (I chose my moment... when the wife was out shopping. What she does not know won't hurt her, but it will me if she finds out).

Take note of the slot at the bottom of the case, marked in yellow. This is to hold the back end of the PCB when you reassemble. Miss that and you'll be in a world of hurt. It won't go back together if you have the case upside down. Please don't ask how I know this!
http://www.ausjeepoffroad.com/forum/...1&d=1503657053

Step 4 - Solder the terminals:

This step is not for the faint-hearted. Practice your soldering skills on something less expensive first. Make sure you have a good quality temperature controlled iron. If it's not temperature controlled, don't go near it for PCB work. Mine is a 46W Goot from Jaycar. It sometimes struggles with automotive work. I notice they have a pretty good looking 80W one here: https://www.jaycar.com.au/goot-240v-...-iron/p/TS1430
Also get the 0.3mm tip. This is PCB work - not plumbing!
While there, pick up a tin of electronic cleaning solvent and PCB lacquer. You'll need them later:
https://www.jaycar.com.au/circuit-bo...y-can/p/NA1002
https://www.jaycar.com.au/electronic...y-can/p/NA1008

Oh! Get solder too, and an iron holder - preferably one with a tip-cleaner built in. Make sure the workstation is comfortable. You're going to be there for an hour or more. This is my station. Note the magnifying lamp. It's great. You may or may not need one depending on how good your eyes are. Working with one is an acquired skill, like drinking beer. (More on beer later. Right now you need to be stone cold sober and have steady hands. Keep remembering how expensive the TCU is to replace if you get this wrong!)
http://www.ausjeepoffroad.com/forum/...1&d=1503658416

The terminals to re-solder are the ones below. See "Tip 5" here: http://jeepswj.com/tips/
http://jeepswj.com/wp-content/upload...ix-251x188.jpg

Just melt the solder and daub on a little more fresh solder. If you make a messy blob, clean the soldering tip and re-melt without daubing any on. This will remove some solder. If you make a REALLY big mess, get an old plastic Bic biro and pull out the ink/point. (Remember making blow-guns at school?) Melt the solder and use the biro in your mouth to blow away the excess. Be careful where you blow it to. Always blow towards the edge of the PCB, never onto it.

Take your time. Stay calm. If you start getting frustrated, go do something else for a while.

Step 5 - Clean and Lacquer:

You remembered to get the cleaner and lacquer, right? Take the PCB to a spot where a bit of spillage will not matter. I did mine on the road outside, but I live in a cul-de-sac. It might be a bad idea if you live on Bourke St. Don't be too concerned about environmental contamination. The cleaner will evaporate before it goes 10 feet.

Put on a set of gloves and give the PCB a good dousing with the cleaner. Flush away any grime or greasiness. Set it aside for about half an hour to dry, then spray it with the lacquer. I gave mine two heavy coats each side, with some run-off. This is not decorative painting, it's protective. Mine looked like this when done:
http://www.ausjeepoffroad.com/forum/...1&d=1503658886

Step 6 - Reassemble:

I don't have any pictures here, but if you have gotten this far I am sure you can figure it out. Follow the steps in reverse, ensuring you get the PCB into the housing the right way around.

You'll need a zip-tie to hold the TCU back in place.

I ended up prying out the ash-tray module to be able to wiggle in the console. Your milage may vary.

Step 7 - Test drive:

Okay, now you can go get beer and reward yourself for a half-day well spent.

More "Jeep Geek" from "Cheap Jeep" to come (if you like this stuff).

Excellent write up well written. More please.

Thanks.

I'm down with 'flu at the moment (I've just been reduced to a statistic) so it might be a while. I want to do the gearshift illumination one next, because I have seen heaps of info on replacing the Electro-Luminescent membrane with LED strips, but none on just replacing the EL driver - which is far cheaper & simpler.

I also want to do the OBD Boost gauge.

I believe Hoobz has an Arduino project brewing also, but he's staying tight-lipped about it until he has it working. Jump in, Hoobz, whenever you are ready.

Great writeup JeanLuke.

Ok ok

I have to admit


:D

I've got a man crush starting :D
You bloody legend Jean

I've had zero luck googling the universe to get onto a good contact about this topic, what you contain in your head :D


Very interested in it allll


To cut a looonng story short...
Are you a member on pirate4x4? I started this thread
http://www.pirate4x4.com/forum/elect...l#post41760737

The replier has answered quite a few of my thoughts by accident, and headed my thoughts in unexpected ways. Good stuff

I have sooo many questions:D

You maybe should have kept your talents a secret
I'll try to only annoy you with question bombing when I hit walls

I want to experience doing my project on my own, with no help, apart from basic research. No cheating

There will be failure but keen to solve

The most annoying aspect of destroying the WG engine this weekend is it will probably distract me from my study of C programming and arduino fun too. I've been loving it, the head pains included. Hey, I'm just an old school carpenter after all:D

Got
To
Resist

I'll just have to budget my time wisely

What is it you are trying to accomplish with the Arduino project?

If it's a standalone ECU, there already is one, open source actually, search Speeduino and you can look at the code to understand what's going on.

For a standalone TCU, there's a guy who built a Mercedes 722.6 (same gearbox as on the WG CRD and WH CRD) controller and it's using an Atmega 2560 so it's possible. A transmission controller is much simpler than an engine controller, it will boil down to a state machine which jumps between states based on few parameters (RPM and load for instance).

You can also ask here :)

The original Arduino project isn't ECU or TCU related, but, I am very interested in ECU TCM programming, and Arduino controlling an engine and/or tranny is high in my thoughts also.

I have the Mega 2560 myself

Do you have a link for the 722.6 controller info?

I will be asking here also now.

Thanks heaps, much appreciated information for sure.

Should I start another thread on ECU TCM programming with Microcontroller thoughts on Ausjeep Jean and Adrian?

This is the 722.6 controller:
http://www.ofgear.dk

Nice bit of kit, I had one in my possession for 15 minutes before I had to ship it to my mechanic friend for installing a WG CRD drivetrain in a JK.

You can start a new topic or hijack mine:
http://ausjeepoffroad.com/forum/showthread.php?t=146593

I originally thought about reading the hex file of the WG TCU (or TCM if you want to call it that) to add new axle ratios. We have the tools and knowledge to do it but lack the actual time/motivation.

I had a hell of a time trying to get my TCM reprogramed when I changed diff ratios from 3.55 to 3.73. I sent it to the states but they couldn't read it. Sent me one from a SRT8 that worked kind of but would go into limp when low range was selected.

I ended up buying a TCM from a USA based wrecker after discovering that all USA WK CRD's are 3:73 factory ratio.

To this day I have not been able to find anyone who can reprogram a TCM/U from a WH/WK CRD. If I had of found the OFFGEAR site I probably would have purchased that kit.

When you say reprogrammed Clarky, was there confliction over transmission input speed/output speed/engine rpm and tone ring readings?

Yep, something like that. Interestingly it wasn't an issue if I disabled the ABS by disconnecting a wheel speed sensor.

Hey Clarky, I read in jeepaction mag about a bloke with a commander who had his computer done by JeepKraft when he went 4.1 gears.

Yeah, the WG uses the wheel sensors to drive the speedometer and to check for transmission slip. If you change diff ratios you'll cause transmission slip errors. I *thought* there was a diff ratio setting available via a drb-3 tool. No?

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A question;
If it was 'just' the signal from the wheel sensor causing an out of expectation with the programming parameter/algorithm (and then a resulting malfunction), couldn't a micro controller be used to intercept the wheel sensor signal, process it by the 1.1(example of a ratio change), then outputting the original sensor signal by the 1.1(still only an example) changing the signal going to the ECU TCU? Fixing the issue?

Or am I missing something?

I cannot see why that would not work, except it would throw out the OBD speed measurement. I'm not sure the wheel sensors are linked directly to the TCU. In fact, I'm not sure where they are physically wired to. The primary function of the wheel sensors is for the ABS, so I would expect them to be connected to this system. The TCU could be getting it's data via the bus system.

I should see about buying one of the new DRB-3 micro-pods. They are down to a couple of hundred now for the knock-offs. I have read that you can set the diff ratio via DRB-3. If so, it is much less "fun" but a far simpler solution.

BTW - Just because I know how to dismantle, solder and reassemble the TCU, don't assume I know how to hack one. I have not tried, but I am not confident I could. There are often several layers of protection programmed into these devices.

I'm thinking you could definitely use a few cheap MC's at a few of the points mentioned to trick the system where needed. Including the dashboard speedo display. But it seems no one is doing that simple trick.

Haha. When you say you could hack the ecu tcu directly I'm sure you could. But it comes down to having the time to get into it. That's the issue hey. Not enough time in the day.

I queried about reverse engineering the machine code of the ec and tc units in the Pirate4x4 thread i started. And yeah, i have not the gear to go anywhere near it. Eg... eliminating wire tapping data echo electronically if you were going to log every wire in and out of the ecu tcu...

It'd be good to set time aside to get into it. I find it extremely alluring. Puzzle solving at it's best

Thinking about my last post, 1st paragraph...

You'd just nedd one MC, like the Arduino mega 2560. With wires going to and from the different sensors and units...to the different pins on the Arduino.

Plenty enough pins in and out on the one MC. Don't need a few.

I'll be keeping an eye on this/related posts. I'm currently studying mechatronics engineering and getting quite involved with Arduino's atm. I've sold my 2.7 CRD, but I've got a couple of 4.7HO now to play with when I've got time

Excellent. Your input will be valuable.
Looking forward to what you find out

I'm also keeping an eye on this thread. Simply becoz I know fart all about what youse lot are talking about!! :D
Sounds like some Terminator 4 shit..I'm so bloody confused! Lol!

JeepKraft wanted $1100 to reprogram (in the states), I didn't think this was reasonable and even with my failed attempts I only spent around $700. If you want to run 3:73 ratios in a WH/XH CRD it will cost around $250au for a TCM from a USA wreck (that's landed here in Oz).

Sorry to digress and hijack this thread

Which specific DRBIII tool would you recommend? I'm looking for a read/write JTEC DRBIII, so I can fix my trans ratio. Axles are 5.38.

ABS is stuffed as the front axle did not come with tone rings, I had them made and correctly installed but the ABS system is still wonky. I've ABS and handbrake lights illuminated. I do have the ABS module wiring diagram and plan to splice the rear working ABS signals. Shhhh.......don't tell anyone, especially the fun police.

Using the standalone controller would make the standard TCU go into limp mode. I don't know (yet) if it will affect the ECU. On the other hand once you have a standalone controller it could be removed and you can just place CAN=bus terminators on the lines going in the TCM. Would that cause a limp mode in the ECU? I don't know yet.

So I've heard...basically the section of the TCU which has that information should be available as a calibration, it shouldn't be hardcoded. The newer JK's use the 722.6 also and the users can set new axle ratios using the Pro-cal module as far as I know, so that would back up my theory about calibration parameters.
jeepswj is working on a DRB3 clone on Android, maybe we will have access to the calibration parameters after all, who knows, I've seen the software, it's amazing but not ready yet.

It's possible, you could feed all ABS sensor signals into an MCU, and reproduce them according to the new gear ratio.

ABS sensors go into the ABS computer, then the speed values are passed to the entire system via CAN. If you look at the wiring diagrams there is a can line between the ABS unit, ECU and TCU. I've heard of two cases so far of sloppy engine changes and forgetting to connect the CAN line between the ECU and the TCU, both resulted in loss of drive.

As far as protection goes, these early control units are not very strongly protected.

Give us a link to the DRB3 clones. I want to reprogram my cooling fan :D

In my opinion, the simplest possible way to edit the data on the TCU for new ratios would be to read everything possible from a WK 3.55 TCU and a 3.73 TCU and compare the data. The ratio should be visible as 355 / 373 somewhere in the data.

Not a hijack.

Title is matching your query.

There are guys in the states who run the speedo drive signal off their WJ transfer case. You heard about that? I was reading it yesterday. Only some cases have the socket

But the above is not nerdy enough.

Let us work out how to do it with a MC, like I want you to.

Would these help with the speedo issue?

https://hmbe.com.au/speedometer-calibratior

http://shop.12oclocklabs.com/index.p...&product_id=59


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It will have some CRC for sure, especially for calibration data, as you don't want a communication error to write gibberish and then the processor will try to read that gibberish.

My job has me looking through and intepreting disassembled code, so it's not completely unfamiliar territory.

Yes and no

It's complicated, well, for me to put in words.

Yes, it could possibly be used (assuming the ones you linked work on the same abs tone ring speed sensor (wheel rpm) signal parameters as the WJ/G's, I don't know) on a Jeep that has had diff ratios changed...but...only then would you be trying to give the tcu/ecu a reading it needs to compute/accept as correctly matching the output speed of the transmission (also possibly engine rpm and tranny input speed).

For example (using very simple whole numbers just to make it easy):
For the speed sensor on the output of the tranny showing 300 rpm, the abs tone ring (wheel rpm) sensor has to be signalling 100rpm if the stock 3.1 ratio diff gear from factory. If so no fault code.

Then you change diff ratio to 4.1.
Speed sensor on tranny output says 300, but now abs tone ring (wheel rpm) sensor is signalling 75 rpm. Now computer isn't getting the expected 3.1 tranny output to wheel rpm ratio and delivers fault code.


Soooo....ah easy...use one of those gyzmos in the links to proportionally change the signal coming from the abs tone ring rpm sensor (wheel rpm) of the new diff ratio to one the tcm ecu accepts. Yes, ecu tcu is happy. But...

...that doesn't factor in tyre diameter, and hence the speedo reading on the dash is up to shit, and reading wrong.

So yes, and no :D

It would work for both tcu ecu and speedo, if you increased (from stock oem) the tyre diameter by the exact same ratio you decreased the diff ratio by. Then it's a yes and yes.

Confused :confused: yet :D

It's pretty easy to follow if you draw pictures and stuff

If it was me, I'd just calibrate the abs tone rings rpm signal from the sensor to what the ecu tcu needs to read from stock. Then use a digital GPS speedo stuck near the dash, and ignore the oem dash speedo

Personally, I wouldn't go as far as to proportionally recalibrate the oem speedo ingoing signal using a micro processor. Couldn't be bothered finding that wire and extra programming :D

No, all good, I understand. I'm a Marine Engineer and Ship's Captain, electronics and engineering are my life lol.

They have been used successfully for both regearing and going up in tyre size. The SpeedoDRD seems to be the favoured choice, the tuning process is pretty simple, work out how for out the real speed is compared to the indicated, for example -7%, set it to -7% and it adjusts to suit. It takes its feed from the tone ring input, reinterprets it to the new mathematical value and then tells the ECU the corrected value.
Now, if you change tyre sizes it has to be reprogrammed to suit but they are infinitely adjustable from +\-99%, it seems to be a fairly idea answer.
BUT! It wasn't suggested to remove your fun making your own module, I was thinking you could use the existing tech in it as a starting point for yours if you wanted. [emoji41]

Doug.


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And nothing I said there is to suggest I'm telling you what to do, I can use and tune radars and radios, I work with 11L NA diesels daily but wouldn't know Raspberry Pi or Arduino if I fell over it for example, I'm here to learn. [emoji12]


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I must be missing something. Which could be because...big day and tired:D

From looking at the info in the links I don't see how it can both tell the ecu tcu the correct oem abs speed signal and have the speedo corrected, because the two are mutually exclusive, by differing ratio changes.

Adjust for correct actual speed (by factoring tyre circumference and diff ratio change) but then the ecu gets a wrong reading (by factoring diff ratio change only) and vice versa

Unless you change tyre circumference by the exact same ratio as the diff ratio change.


Formula comparison could be something like this, maybe?

Tone ring signal going to ecu tcm affect
Rpm= tone ring speed x diff ratio change

Speedo reading affected.
S= tone ring speed x ratio change x tyre circumference

No, it's likely I've missed something, there may be two modules , one for the TCM and that one for the ECU.
I'll have to see if I can find the thread again.


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:D

I'm very beginner.

This thread is helping me very much. Making me think hard.

If everyone ads it will only help. Keep adding for sure. Awesome for you to stay.

The best way is for people to ask, suggest, comment and be peer reviewed. But, it takes a massive amount of humility to do it and risk being corrected, feel a bit silly, when that's exactly how we improve.

I'm throwing myself right out there, and anyone of you guys can certainly teach me when I'm going wrong. If we're all like that, then we'll all get somewhere and learn. And people checking the thread learn too.

I bet there's a few people looking at this busting to type something. They shouod go for it.

I have speedodrd and it works fine with correction for the bigger tires by comparing speedo vs gps.

Anyway, I haven't actually read up on all the recent posts anf have no heads or tails on what's going on tbh.:D

Many years ago, a very wise man (my Dad) said to me "Never be afraid to ask questions, or be involved, it's the best way to learn".
That attitude fits in well with what you said. [emoji846]

Anyway, I've been thinking about what's involved in changing ratios in the diffs, and correcting for that in the TCM. In the older manual systems, it was a relatively simple case of changing the drive gear in the box to provide the corrected information to the speedo. But with the electronic transmissions the information comes from the ABS tone rings right? Is it one feed only? Or are there 2 mutually exclusive feeds? One to the ECU and one to the TCM? If they are both fed from the same feed then it would be possible to make a single module that takes that feed, interprets it in 2 separate sub-units to feed to each modules to correct both, right?



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Speedo fixing isn't too hard. If the ecu tcu isn't fussing over the tone ring speed relevence.

The WJ/G 4.7s are more forgiving than the next model diesels and others. They're a lot more picky.

(*ahem* my front abs is discon too *ahem*):D

Thanks, I wanted to hear from someone local to see how good they are.


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My head has gone a bit foggy, so last post for tonight :D

It depends on the model, I've lost track a bit there. The diesels are much more picky with making sure wheel speed, tranny out put speed and tranfser case selection always are within a certain algorithm formula. If one of them is out >>> Fault code and/or bad transmission performance and engine behaviour.

Oh, there's engine rpm, transmission input speed sensor, transmission output speed sensor, transfer case selection sensor and abs tone ring sensors. Just having one of those out can cause problems for some cars and sometimes they're not so fussy. There's a bunch of variables...which means head aches

As far as the last few sentances you asked, yes, one unit (Micro Controller) could take the one speed sensor reading, compute two different formulas and output two separate different corrected frequency signals on two separate wires. One to the ECU, one to the TCM, and even a third to the speedo if it was required. I think that's what you mean.

PS. Other posters in here could answer much more clearly on model specific electronic architecture to your question.

Hey Hoobzy, My head hurts! :D

I've been reading up links to pirate, Adrian's links and I'm getting a bit lost tbh. Can't see the forest for the trees lol! :p, so help me see the big pic please.

The WJ speed signal comes off the two rear ABS sensors to the ABS module. SpeedoDRD splices into these wires and one does the speed correction accordingly, so no worries there.

The problem is when one changes axle diff ratio and the ecu tcu is not happy, is that right? Can this be solved by as JeanLuke wrote : DRBIII Pod JTEC read/write? If there's a cheapy one that works, would that help?

I'm having problems with my gearbox, in the sense that the gear changes is a bit wonky with 5.38 and 37s. I have gone back to 33s for on road driving and saving the gnarly tyres for the bush. I do have tranny codes, not so happy front ABS sensors, ABS and handbrake lights.