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Howdy fellow, enthusiast. It's been a bit since my original post, which focused on few codes for my DIY big cat reno. That said, I've hit the proverbial wall with CAN BUS shorts. Pinpoint test have resulted in suggesting ECM, eventhough the SDD v 130.07 with FII VCM reads doesn't show that to be a problem. JTIS pinpoint test, is different from Jag workshop manual so its been a bit confusing at times.
My most recent scan resulted in less codes than before after thorough cleaning of grounds, and replacement of few connectors
but the TCM, with P1643 generic ECM/TCM and U1900 which points to instrument panel. Yesterday's resistance check between can + can - shows 60 ohms with all circuits plugged in, and battery disconnected.
When I disconnect a module, I get 120 ohms which I understand demonstrates an open circuit. Nonetheless, inspection of TCM, ECM, and IC showed no signs of damage. TCM was the cleanest of all, yet still I get nothing but communication failure when SDD tries any of the functions with it.
Any suggestions, before I purchase another TCM, already replaced Jgate, which I now believe did not need to be replaced and now it looks like I need break switch replaced since I can't shift. I also checked link cable, hit it with plenty of WD40 and it moves.
Am I doing something wrong? I understand in a BUS network, all it takes is one node to break the chain but I can't figure this out...
Just looking at your diagnostics and I'm not seeing any mention of the climate control system in your CAN list....not sure if you should see it, but does seem odd to not be listed.
The TCM CAN comms path through the climate controller up to instrument cluster, yaw, steering sensors and J Gate...so it might be worth taking a look at the climate control module to see if you have a loom, plug or connector issue there.
Thanks for the quick reply, I've read plenty of your responses in other post, so I welcome your expertise and the assistance. As for the climate control, you're right, I get nothing on it other than AC/Clutch which isn't related.
Honestly, I was going to take the radio and ac modules out as the next part in the chain to check. I figured since my display on the AC isn't illuminating there could be a problem there.
I have literally gone through the entire harness from ECM, corrected all grounds, added new connectors and soldered even one of the grounds. I then headed inside the cabin, took IC off and proceeded to check each module.
In last test run, I have continuity from each segment, except for restraint module, which I believe to be dead. I replaced the JGATE and unfortunately it wasn't the exact replacement.
My original JGate has 11 wires, replacement has 13 wires which relate to S switch or 3 or 4th, the other 11 wires all match. Nonetheless, I was planning on checking CC, but had to travel and won't be able to get back to testing till tomorrow.
I'm glad though, to atleast see I was headed in the right direction, thank you for the response, I will reply back soon as I get back to it.
Took CCM apart today, definitely looks like lcd us fubared. Nonetheless cleaned and tested boards today. Going to try plugging it in tomorrow see what happens. Pretty sure I'm going oing to have to order one on Monday
Wow Closb....I've never seen a LCD in that condition before........however I've only worked in electronics for 40 years ;-)
If that is the front side of the LCD then I would hazard a guess that some chemical has reacted with an antiglare film.
If it is inside the LCD (the gel) then that will be a first from me.
LCDs are fundamentally a polaroid glass sandwich with some electrically responsive gel inside that reacts by twisting slightly thus bending the polarized backlight as it travels through the gel so the light can't pass through the second layer of glass.
There is little to burn as LCDs are very low current. The backlight source can be problematic depending on light source technology and power supply system.
closb, just read your post on the instrument cluster thread....so something else that can happen on our instrument cluster modules is a copper track that can overheat and go open circuit.
It causes some errors with actuator movements but nobody has posted issues with LCD failures or discolouration before to my knowledge.
But if the LCD has somehow become a crispy critter from being overdriven, that would likely reflect back to the module's microprocessor operation and likely take it off line from the CAN Bus chain.
@Gophat Surprised to see that the LCD alone was in some instances 5 times as much of a used unit. LCD is the only damage on the board, I did check to see if that track was burned like some of the others, but no go.
@h2o2steam yeah, firt time for me as well, and I go back to Motorola pagers repairing electronics. That said, it was the only damage to the CC. I was able to get everything in the CAN circuit tested for contiunity and all is well.
I also took the JB off, and discovered the ground on the TCM, was actually screwed on at different place, closer to ground on pillar. It started to rain lightly, so I was only able to plug everything in so I can test tomorrow.
This is unless the place where I placed the ground is incorrect? When I started working the vehicle, it looked odd that the ground wire was by the door, wasn't till I dropped nut, that I found the extra nut in the carpet which I assumed was meant to go here?
Well folks, its official Climate Control Module, aka Automatic Temparature Control is fubared as expected due to LCD damage. Still getting can network, I also got a strange code I cannot find.
"diagnostic trouble code 0x9242 has been read from ATC"
Moreover, due to rain keeping me from checking electrical, I took some down time to repaint the AC module and clean the buttons. Since I figured it would need to be replaced, figured it was a good opportunity to improve my spray painting skills. Couple of coats of cheap $2 generic high gloss rattle can, wet sanded with 300 grit and finally polished it with some Turtle wax.
Not the best materials to use, but it was my first time. Minus rubbing off some of the black on the buttons, I was thoroughly pleased of how good it looked - minus the fact it doesn't work..
FML - part arrived yesterday with broken button, waiting on seller to respond. Quite frankly I am not surprised it was damaged due to how it was shipped. Seller packed in an envelope with bubble wrap. Luckily I have my buttons I can replace it with, but I cannot open the part, and am also concerned if the hit was that hard, maybe something else is broken.
Either way, my hands are tied till seller responds!
It pops my corn and boils my water. Seller finally responded with typical BS - I packed it in heavy duty bubble wrap, please ship it back and take note of our shipping guidelines. So going to get ebay involved today, escalate the issue and get my money back. And people wonder why this world is in the miry pits.
Am i seeing Acme on the package labelling?
Well ponder no further ...we all know from our childhood Wylie Coyote had a disastrous run with any Acme product he tried to use against Road Runner.
Judas Priest....a simple box and some shredded paper would have not only been better to protect the product, but eliminated much of the plastic packaging which is a curse.
Bubble wrap is OK to suspend and isolate a product but it really needs a hard shell to provide first point of contact protection, but sending that part in just a bubble bag with some additional bubble wrap is putting too much faith in careful handling in the delivery chain.
Remember the courier's golden rule.......Anything marked fragile must only ever be thrown underarm!
I am going out of my way at work to package items to my customers with easily disposable packaging when couriering, as they are mostly rural and have no council waste pick up processes nor recycling sorting.
So I either send items in cardboard boxes filled with shredded office waste papers or crunched newspaper, or if the product's box itself is sufficiently strong with good internal packaging I wrap it neatly in very heavy brown paper.
I don't want to be sending my customers' a problem that they can't easily burn in their log burners or compost if they wish to do so.
Sorry for delayed response, but been working on my money making project for past two weeks. That said, I returned the unit and have not ordered another one, worse I seem to have lost communication with the entire CAN network now. I'm convinced its my DLC connectors or if not, my USB cable. I spent a good amount of time yesterday testing the network and was getting 2.5 volts from both CAN high & low.
I took the harness apart in the only part I had not, which is the junction box, right after the power distrubution block. I did find several crimped cables, one that looked really bad, I straightened them all out and still no go. Unfortunately by end of day, I was mentally fried and just called it quits.
Consequently, I did a resistance test between high and low and am getting the 60hms. I also checked power cable on DLC pin 16 with grounds and they worked fine. Continuity between module to module is fine and once I straightened out the crimped cable, I did get different volt readings from can. I looked yesterday on the shop manual to find exact measurements, but to no avail other than resistance checks with pin test.
I'll admit, I hit wall yesterday so I'm going to take the day off and focus on my work project before I dive back into the bit cat rescue. Any feedback is appreciated, thanks again for all your help!
By the time you buy a new unit, it might be about the same cost and this gives you many more features.
Dennis also has several posts on installing single and double din units with great results and less money than conversions with again more features than the OEM units.
Last edited by Dell Gailey; 04-12-2022 at 01:27 PM.
Hi, my big cat brethren, hope everyone is doing great. I know it's been way too long since my last update, so I wanted to chime in on my progress, so here it goes...
I took about a month off from working on the car just to clear my mind from hitting the wall. When I finally decided to get back into it, I started from scratch. This meant checking the wiring harness from start to end at every single point of contact. I ran a continuity test first to ensure there were no issues. Once I cleared those, I wrapped the harness in new high-temp cloth tape and tucked it back like it was when it left the factory.
I then moved on to ground points, I know this is stressed over and over, and I'll admit I like most ignored the KISS principle. I used a wire brush to clean every single ground. Still, most importantly, I followed the electrical diagrams notes with positions, superficially the ABC which determines which goes first, middle and last on a ground stud. I now know it was a bad ground contact that was causing my dreaded CAN bus. Coincidentally it was the main one on pillar A which had the positions reversed. It turns out the problem was right in front of my eyes the whole time, but I ignored it because there were no signs of rust or anything.
I also went ahead and changed the negative battery terminal along with new wiring and new lugs. I still have to do the positive side as well.
Once I knew the infrastructure was solid, I moved on to parts, and I replaced the automatic climate control (ATC) and the transmission control module (TCM). The ATC came in first, and that worked without a hitch, except for now I had issues with ECM not responding, so I figured I must have FUBARED something since that was never an issue. Notwithstanding, I exited SDD and ran a new session, but still no read from ECM. After several scans, it finally picked up the ECM and asked me to proceed with reprogramming it.
This was pivotal because I was under the impression that my VCM2 could not be used for programming, and any attempt would brick my ECM. With no other options but to accept, I clicked and hoped for the best, and what do you know, after what seemed like an eternity, I got the programming completed, and just like that, my SDD showed the green tick for ECM. I will say, I did connect an external power supply to my VCM since I had read that power fluctuation during programming was the root of most problems.
So now I'm back in business and moving on to TCM, which was ordered last week and was installed this Monday. Unfortunately, when the unit arrived before installation, I noticed two pins had heavy oxidation. One of those pins happens to be a power ground pin.
Nonetheless, I took pictures, plugged it in, and powered everything up since I have a 30day window to return it. The seller's messages have gone unanswered, and I now have eBay involved. I didn't clean the pins because I wanted to see if the TCM worked out of the box. Moreover, it has a tamper-proof sticker on it, so I figured it would be best since I only have 30 days to return it.
Consequently, here is what my current SDD scan shows. I was excited to see that the TCM finally showed a green tick mark. Unfortunately, that's as far as it went because I get communication errors when I try to run any TCM-related diagnostic like the "adaptation clear," which results in "TCM communication error."
I will wait for the seller or eBay to respond before I try to do anything more with this TCM. I think that since one of the oxidized pins is a power ground, that could cause the communication error. Similarly, if it is, without opening up the TCM, I won't be able to tell if it's just a bad contact or if that oxidation led to other component failures.
Today I am finishing removing the differential so I can install a new fuel pump and sending unit, and then I'm ready to fire up the big cat once this TCM issue is resolved. Sorry for the delay in updating,
03-10-2022, 11:48 AM
Dreaded CAN Bus faults
