My girl's GMT360 2002 TrailBlazer & A Service 4WD dash message

[ORVietVet]

About a week ago, got up and TB would not crank and had a dead battery. Did locate the parasitic draw to a plugged in cell phone charger that the plug lights up when installed. Been a week since all this with no parasitic draw problems. I have a Power Probe PPDRAW tool that I use to monitor and found no further problems......EXCEPT....the SERVICE 4WD light is now on when started and stays on. Is causing no parasitic draw problems. I pulled codes and got U1026-Lost Class 2 Communications With ATC.....U1000-Class 2 Data Link Malfunction and C0550-ECU Malfunction.

There is no driving problems. The Drive selection switch does not light up. It is a 2wd-awd-4hi-4lo switch. I checked the ATC fuse by sight and both sides with test light. I also located the ATC module, d/s end of dash behind pop off panel. I unplugged all 3 connectors and plugged back in with no help.

The strange thing is that all was good till the dead battery and then this light comes/stays on now. I have also had key off and pulled the ATC fuse for 1 minute and reinstalled and no luck. My next step is to reattach my Foxwell NT710 GM only scanner and try to see where the communication problem lies.

 

[ORVietVet]

Codes found, U1026-Lost class 2 communications.
U1000-Class 2 data link malfunction.
C0550-ECU malfunction

Then found at GMTNation Forum, that the TrailBlazer TCCM-Transfer Case Control Module that was installed in all the 2002 TB's typically do fail. The problem was corrected in 2003 and newer TB's. I bought a 2003 TCCM from a seller at ebay and he is programming it to match with the 2002 TB and I will install and should be fixed.

 

[ORVietVet]

According to USPS tracking, I am supposed to get the incoming TCCM tomorrow afternoon. I will be either installing it tomorrow afternoon or likely Saturday afternoon-busy Saturday morning, or sometime Sunday. I will post the before and after pics here.

 

[AuroraGirl]

 

[AuroraGirl]

 

[ORVietVet]

Ok, new TCCM is installed and all is working. Scrapes and some blood involved. SERVICE 4WD light now comes on to communicate and then goes out and the indicator lights up as should. Not too bad of an install. The hardest part was the module in the holding bracket and then reinstall the bracket, with 2 locator pins and 2 inch wide clip ears into the aluminum bracket mount. Gotta hold the tongue just right to line up and push in place. I now have the old TCCM and will contact the seller at ebay and see if he wants it. If not and someone here wants it, PM me and we will talk.

 

[ORVietVet]

 

[SK101]

i do like the trailblazers, dad has 2, well 1 than runs. The other needs pretty much all new steering and suspension, but he lives on gravel roads, thats just how it is.