Intermittent CAN C Bus issues
So, this car has some serious issues. Customer just bought this vehicle from a Dodge dealer and now the owner is stuck with it. They basically said it was bought ‘as-is’.
Anyways, it has bunch of codes. I attached a picture of all the codes. This problem is intermittent. Most of the times, the car will start and run fine and then all of a sudden it will go in limp mode. Some times the car will not start, as in nothing happens when pushing the start button. Sometimes, the whole dash lights up like a xmas tree.
All the times I looked, the scope shows good communication. What is the best way to tackle this? Has anyone else experienced this before? I have not done much diagnostics, trying to find the best way to approach this.
Hi Tayyab, All the times I looked, the scope shows good communication. Where are you testing for that? By looking through your DTCs, it looks like a large section or all of CAN C is going down. I would start by going through the CAN C diagram and performing a wiggle test around the Star connectors and any of the other connectors you can easily access. Maybe this will recreate the concern. I…
I have always looked at cars from a mileage perspective. 2019 3 years old, does the mileage match the computer? ABS has a useful life expectancy. The magnetic strip under the sensor or the wires leading from the sensor to the ABS computer. Take a picture of the DTC’s and erase them the computer program runs on a timed basis. DTC’s slow the program and cause a time out glitch.
Can you elaborate on the magnetic strip and sensor you are talking about Mark??
Each axle has a hub and on each hub there is a bearing a magnetic sensor and a magnetic strip that revolves with the wheel and the sensor picks up the individual magnets. In the strip. there could be a broken wire from the sensor do to accident damage. start with the basics erase the DTC’s.
Can you get the fault to happen?? If so connect a scope to CAN C when car is not broke. Then see what happens to the waveform when it breaks. Then you can disconnect modules one at a time at the STAR Can connector until you isolate the offending module or circuit. Have you looked at a diagram? Do you understand how the CAN C bus works on this vehicle??
Each module is connected to a star connector and the Star connector ( white the green plugs) is connected to the Gateway if its a Star Network … Other Chrysler Daisy Chain ,Hub and Stub Topology layout on witech would show this to be star with all modules connecting to it . also need SI only show how connected on the bus …..I'd start with short circuit diagnosis pull some fuses see if short to…
Ahmad, Here is a powernet work sheet that I made showing the star connectors.
That's the problem. I've had the car for about a week and zero problems. I check multiple times a day, but no progress.
I had a 2019 Ram truck at our shop that had a very similar situation. Sometimes it would be fine, other times the dash would light up like a xmas tree. At times the windows would not work, and it would go into limp mode, along with other problems. Long, long story short - it turned out to be the star connector in the kick panel area on the driver side. After replacement, no more problems. We…
Hi Tayyab. There are two Star connectors for the Can C network in your car. One is located behind the glove box ant the other is located in the trunk. Look closely at the star connector in the trunk for any signs of corrosion and do some wiggle test to duplicate the problem. Voltage on this network is very low so any corrosion (resistance) can cause a lot of problem. Regards
If you can duplicate the concern, Isolate the main modules by disconnecting any modules not needed for the vehicle run at the star connectors. On is a jumper wire from one star to another star connector. You'll need like PCM, BCM, TCM, and Security for the vehicle for it to start. If you don't duplicate the concern, then I would start plugging one by one back in.
2 years old sold ‘as is’? Something sounds fishy. Accident/ salvage/ etc. ?
I've checked all STAR connectors, they are ok. I have scoped pins 6 and 14 on OBD2 and all signals look ok. The problem is intermittent and I cannot get it to duplicate while I am diagnosing it. I've tried a wiggle test on the harness, tap test on the modules and even heat test by turning up the heat in the car. So far no progress. I will post update if/when I find the issue. I've checked…
Hi Tayyab, Scoping at 6 & 14 of the DLC probably won't give much insight as that is Diagnostic CAN C. If you're going to use a scope to diagnose this issue, you would need to scope CAN C either at the gateway module or some other easy accessible location.
Thanks to everyone for their input and help. I drove the vehicle about 2 hours and it finally started acting up. Turns out the tire pressure module was the culprit. Unplugged it and drove for another 2-3 hours and no other issues!