SO I have come across in other threads and have used search to try to find answer, no luck So
I have the traction fail message, service stability trac. I have installed a complete new front end Had the Caddy (old Hummer Dealer in town) dealer do alignment, Yaw sensor is communicating and working still have the message. So in researching I see there are a couple BCM's. Where is the one not communicating located? What else should I be looking for? When driving with stability trac on the truck shudders when I take foot off gas. Drives much better when switch is in off position. I have a 2009 H3t with the locking differential buttons and the I5 engine which looks like it was replaced at one time. Thank you in advance for the help! I want to start driving my new toy!
Marc

 

There are 4 computers, BCM, TCM, ECM, and airbag computer. BCM controls the TCS/stability. Are you actually getting a BCM communication error when the dealer connects to it, or are you saying it just doesn’t seem like it is communicating? Have you noticed any other weirdness lately?

 

 

Have the connectors been checked for corrosion? If they look good, there is probably something wrong with the BCM and it might need to be replaced. Mine went bad last year and it also fried my ECM

 

That is where we think we are at now. I had the clogged sunroof drains carpets got drenched and here we go. Thank you for the help and response

 

Ah man, sorry to hear that. Yeah very good chance your BCM suffered water damage and components inside are corroding. Pretty sure mine was defective from the factory, likely due to a bad capacitor or failed keep-alive-memory module. I could hear alternator whine through my stereo until we replaced the BCM and then the whine went away. Mine would randomly not start, then some days TCS/stability would fail, especially on days of high humidity. Then one day it would not start at all and that's when it finally failed. Best of luck, I wouldn't wish this issue on anyone. Make sure you find a dealership that is familiar with the Hummer security programming process. Because GM cut the Hummer division almost 10 years ago they do not staff their support engineering teams specifically for Hummer. We had to track down a former Hummer tech at a local Cadillac dealership; he knew the process better than GM (the process is slightly different than any other GM vehicle). The process is required any time a new computer is introduced to the Hummer electronics system, especially BCM/ECM.

 

Woooops........ you forgot the TCCM. Transfer Case Control Module. Woot!

 

A lot of info & help and it is appreciated.......Will keep you posted as to the outcome

 

Doh, I sure did! I should have known better too since i just had to rebuild my tcase.

 

So all the computers are communicating now & working. Wheel sensors working and I still have the Stability fail / service Traction Control warning. I am about to give in & sell this truck that I so want to drive. Any suggestions? Your help is appreciated.