Truck is acting like tow/haul is on 100% of the time. 1-2 shift is very hard and I have to wind it up to approx 75mph before it will go into high gear. It did this the other day. I pulled over, shut it off and started back up and it was fine. It also bucked on acceleration this morning and "service brake system" was displayed briefly. Friend of mine suggested ign switch might be the culprit

Codes:
U2104-- CAN Bus Reset Counter Overrun
U2105-- CAN Bus Error ECM
p0880

Dropped it off at the dealer this morning. I'll know this afternoon how many zeros will be attached to the end of my check! :(

Ended up being a chaffed wire to the FICM. $206!!! All is well

Ended up being a chaffed wire to the FICM. $206!!! All is well

Very interesting. I have seen those codes on my own truck and a few other trucks, but it never stayed long enough to pinpoint the problem.

Been shifting fine all week. Guess they fixed it right the first time!

Mine did something close to your symptoms. However, I had couple of TCM codes. Took it to the dealer and did some kind of updates, all is good now. It has been at least 2 months. :cool:

Do you know what wires?

Do you know what wires?


I do not. Haven't even opened the hood since I got it back. I have to change the oil this weekend though, I'll try to take a look and see what I can find.

I looked over the weekend (not too hard) and couldn't really tell or see anything that would indicate where the mechanic did any work to the harness.