We had a total of 21 days at Ryan Chevrolet last month. They still have not been able to come up with a solution. They say they can get any hard codes out of it and when they drive it, it doesn't act up. I picked it up and about 15 miles later, all the symptoms were back. I wonder if they just are scared to put in the required time it will take to fix it, or if they actually dont have a clue as to what could be wrong. I purchased an inexpensive scanner (CP9575 Actron) and got the following codes.
P0700 Trans control system MIL request
P2544 Torque mangment system input signal A
U0073 Control Module communication bus A off
U0100 Lost comunication with ECM/PCM A
U0101 Lost communication with TCM
It seems to me (not a mechanic) that the problem may lie with the TCM or the communcation cables/connections that feed it.
I see that there is a TSB that gives some of these codes and a possible solution. (Backed out terminal in transmission wiring harness).
Does anyone know where the TCM is located and which wiring harness they could be talkng about??
Any help will be greatly appreciated.
Register today for free or log-in if already registered to remove this ad!
I took it back to the dealer after we had a "walk home" incident monday morning. the engine died when coming up to a stop. It finally restarted after about 5 mins and many tries. Same symptoms plus engine shutting down. Dealer called me today around noon saying it was fixed. GM said the PCM was bad and to replace it. They did. I picked it up and drove it about 4 miles. Same symptoms again. PCM was apparently not the problem. Took it back to them (insert disgusted look here).. Told them to try again. :-(
Per GM customer service request, I took it to another dealer. They have replaced the BCM now and say they have the problem resolved. The mechanic that worked on it is going to drive it for a few days just to be sure. Here's hoping. I will update again in a few weeks.
I picked the Tahoe up. The mechanic had put about 90 miles on it and said he had no problems and the issue was fixed (replaced BCM). I drove it 6 miles. Still has same problems going on. Took about 30 minutes of video while driving around to exhibit the problems. I took it back to the dealer the next morning and showed the video and gave it back to them.
Make sure the grounds on the back of the motor are secure and corrosion free. If you are unsure of the grounds then relocate them but do it all right, with soldered wires NO BUTT CONNECTORS!!! also make sure there are no butt connectors on any of the wires coming off the ignition, for an alarm or anything like that, if there is solder the wires, I have learned that the new line of chevys are very finicky with the wiring, its a mulit plex system that uses low voltage pulses and any thing that adds resistance is bad news and will have you chasing a ghost.