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!
Working on a DTS with a no start condition. Can’t communicate with the ecm or tcm. Have 5v on the reference signals. Also have fuel pressure. I can monitor the BCM and the ignition switch seems to be working. The previous shop replaced the intake and cut wires going over the rear head with the battery still connected. Not sure if that could’ve blown something out. Had to run a separate power supply to the ecm. It was missing that signal from the rear fuse box.
Last edit: 4 years 2 months ago by Tsedlak. Reason: Spelling errors
my approach to no coms is very basic. Powers, grounds, and ability to communicate. I’d also recommend factory diagrams and not Mitchell diagrams for network problems.
Often when facing these types of problems I think it’s usually not the best idea in many situations to not run new wire because you run into the exact issue that you’re having (Don’t ask me how many times I had to learn that lesson).
If the shop cut wires, how many wires are we talking?
Making Pressure Differential Sensors (PDA Sensors) for pressure pulse diagnostics.
Currently servicing Central Texas.
By any chance have you scoped your comm lines to see what they look like? Or OHM them out to see if you have the proper specs? If your comm lines look decent then check for comms at each component and go from there. Also since you said someone cut the harness did they happen to put the wires back to the correct wires? Thats something I would start with as well.
