What's up with all these codes? 2006 LBZ

DaninMN

New member
Feb 16, 2024
2
0
1
Minnesota
Hi, I'm new to owning a Duramax and new to this forum, wondering if I can get some expert advice. I bought a very clean Arizona LBZ back in September and it has been fantastic - no issues whatsoever until a week ago. Wife took it into town (short trip) and the ABS & parking brake lights came on and the shift position indicator light went out, she forgot to tell me about that and I took it out later that day with no lights or any issues. Next day I took it out and the CEL came on - scanner said P0826 and P0827 (up and down shift switch circuit). I checked fuses and re-started a couple times and all lights went off, we drove it that night with no issues. Next day i had both brake warning lights, no shift indicator and the CEL on and with no key in the ignition the battery warning light stays on - never shutting off. Now the scanner has added U1000 (class 2 data link malfunction), B2550 (backup lamps control circuit malfunction, B2575 (Headlamp control circuit malfunction), B2961 (key in ignition control circuit malfunction), B3802 (parklamps request control circuit malfunction), C0040 (RF wheel speed sensor circuit malfunction), C0055 (both rear wheel speed sensor malfunction), P0826 and P0827 (up/dn shift switch circuit) and U0101 (lost communication with TCM).

That's a lot, thanks to anyone still reading this... Anyway I'm hoping someone can shed some light on what i aught to be looking at or testing, gotta be a snowball affect to have all these issues just appear within a few days time. I plan to bring it to a local diesel guy but he's so busy I haven't been able to get through to him so gonna see what I can do in the meantime.

Thanks for any help!
Dan
 

Ron Nielson

Active member
Oct 11, 2009
691
116
43
Berryton, KS
Disconnect the negative cable on both batteries for 15-20 minutes then reconnect and see if there is any improvement. Beyond that, I think you should leave it alone so that the diesel guy has a chance of seeing what the problem is without having to fix something additional that you did while you were trying to fix the problems.
 

DaninMN

New member
Feb 16, 2024
2
0
1
Minnesota
Thanks for the response Ron, before seeing it I had the thought, I wonder if pulling all those fuses to test them could have caused all the circuit malfunctions? I cleared all codes with the scanner and then re-scanned and only the constantly-on battery light and the original up/dn shift circuit malfunction codes remained so I dug deeper into previous posts on those codes. Apparently there is a wire on the shift lever that gets pinched and shorts out the system. I went out and started wiggling the shift lever and saw the battery light flicker - aha! i then tilted the steering wheel up and the light went off completely. I'm going to open up the steering column and hopefully find my problem.