U0101 and U0129 Error Codes

Wiggums · July 18, 2019

Nice, the other Silverado we own and almost never drive is now showing error codes. This one has only 1,700 miles.

U0101 - lost communication with TCM, and

U0129 - lost communication with brake system control module

At the same time, I am going to ask them about reprogramming the transmission so it stops jarring me from a cold start.

I hope it goes well, taking it a couple days from now.

HondaHawkGT · July 19, 2019

My money is on it being a wiring harness issue. Probably rubbed through somewhere and it's shorting modules to ground.

Wiggums · July 19, 2019

1 hour ago, HondaHawkGT said:

My money is on it being a wiring harness issue. Probably rubbed through somewhere and it's shorting modules to ground.

Yeah, it stuck me the same way, something got loose since both were about communication between the car and electronics. Just a little jiggle and I'm good to go. Thanks!

Bikeman · July 19, 2019

Mine flagged those same dtc's. It happen during remote start. They were immediately went to history. Generally communication codes are disregarded unless they active or reoccurring. Usually a module or 2 didnt "wake up" as quick as the ECM and flags erroneous codes. Mine never came back btw

Wiggums · July 19, 2019

3 hours ago, Bikeman said:

Mine flagged those same dtc's. It happen during remote start. They were immediately went to history. Generally communication codes are disregarded unless they active or reoccurring. Usually a module or 2 didnt "wake up" as quick as the ECM and flags erroneous codes. Mine never came back btw

I haven't used remote start in a month. It came up while I was driving, I am not even sure if it occurred right after starting it since the check engine light isn't bright. I wish it was bright so I could see it right away and know if it happened right after starting it. It was my phone that notified me since I had an OBD II from the auto insurance company and got the message about five minutes after starting it. I'm still not sure if it's quick as this was the first time.

My dealer thinks it's going to take a while so they're having me come in early in the morning. I'm also having them fix other niggling issues. Since I see it as communication codes, I don't feel a sense of urgency.