Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
OK folks. I am new to some of the more advanced troubleshooting stuff and I hope I can get some guidance here.
I have a 2011 F550 cab & chassis (6.7 diesel) kitted as a bucket truck with an Altec system. Been experiencing some strange problems and I thought I had narrowed it down to a canbus communiction error, but now that's looking less likely.
Here's some more background and symptoms. The bucket assembly monitors the high speed canbus, but does not write anything to it. When I plug my Launch X431 into the truck, I am unable to communicate to any modules. When I unplug the module that monitors the canbus, I am able to scan the system. The PCM shows that there was a recent canbus A failure.
As long as I leave that module out, I can talk to the truck just fine. Reconnecting it results in the same behavior. I tried replacing that module and got exactly the same behavior.
So I measured resistance on the CANBUS lines with the module removed and plugged in. I got open circuit -- no resistance value at all -- which led me to think that something had happened to the canbus terminators.
I pulled out the scope, and while the waveform doesn't look perfect, it doesn't look like the examples I found online of "bad/missing" canbus termination.
If I leave the bucket module disconnected, none of the bucket truck functions work, so that's not an option.
Topic Author
