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does anyone have a good reference for CAN diagnostics? This mess of a car came from a Ford dealer trying to put a TCM in and couldn't program it. It has multiple Uxxxx codes. Now, normally, if there is no communication with a module, i can work that one out. this one has me stumped though. there are codes for no comm with tcm/pcm/ipc and i can communicate with all of them with the scanner. ive read somewhere that the instrument panel cluster acts as a gateway for all the other modules so it would make sense if there were a comm error with it, that it would drop all the others, but i can communicate and there doesnt seem to be any irregular voltage at the dlc.
Have you checked resistance between pins 6 and 14, at the DLC. Key off, system powered down (some will say disconnect the battery), you want to see 60Ω. That is the High Speed CAN. Do the same check at pins 3 and 11, for the Medium Speed CAN.
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
List the U codes, please. Do you have a scope? Does the waveform look clean?
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
Do you know if this vehicle has a gateway? If it doesn't, 60 ohms means your main lines are good between the modules with terminating resistors. You can eliminate all of the modules that HAVE u codes since those are the ones telling on the one(s) who they can't communicate with.
I’d clear the codes those codes can be leading you down the wrong path. During programming even when it goes normal you always get u codes. I’d honestly just check powers grounds data lines at the tcm and see what it’s missing
I have cleared all the codes and the same ones come back. I’d have to look when I get back to work but, pcm can’t talk to tcm, tcm can’t talk to ipc, ipc can’t talk to the tcm, abs doesn’t like what it’s seeing from the pcm and tcm. Something else can’t talk to the ipc. U0101, u0155, u0401, u0402. Through the scanner I can talk to all of them. The ipc is supposedly a gateway for the high speed LAN. The TCM on the car is NOT programmed to the car because there was communication error between it and the ipc.
I scoped the high speed data line and there was no irregularities when I compared to Fords diagnostic. I know there has got to be something simple I’m missing
Where did you check for 60 ohms at?? Pins 6 and 14? If the IOC is a gateway module that test isn’t valid. You’d need to check it at another module I’d check for 60 ohms at the tcm high speed terminals. The pins 6 and 14 go just to the gateway if it’s laid out like a Chrysler.
If you can check live data with all the other modules besides the tcm I’d be focusing on the powers grounds at the tcm. The dealer may not of diagnosed it as a bad tcm they might of been just asked to program a new one from the customer. It might be missing a main ground where it’s not powering up to program it
actually, i can communicate with every module on this vehicle. we do not have a ford ids, which i think would be a great help, as they have a specific test to see which module is actually working. i know that with fords that a come issue is the tcm, but it causes a no-start, which i do not have but there are communication issues all around. i may try jumping from tcm to icp to see if i can get any clear up.
