the heck is this? uncles truck had it as a DTC. I read somewhere it isn't good, just curious what the problem might be, his screename is "gmclly20054x4"

This is the communication lines that all the computers in the vehicle communicate with each other on. Did it set a code? Possibly a loss of class2 communication?

I have that code... I cleared it and still resets.
How do you correct the problem?

This is the communication lines that all the computers in the vehicle communicate with each other on. Did it set a code? Possibly a loss of class2 communication?yes it set the code, I cleared it and it hasn't reset yet.

If you can get me the code that it set, I may be able to help. There is a number for the modules that corresponds to the code. U1000-U1255 I believe.

Control Module ID Number
Powertrain Control Module (PCM) 016
Transmission Control Module (TCM) 024
Transfer Case Shift Control Module 026
Electronic Brake Control Module (EBCM) 041
Rear Wheel Steering Control Module 048
Body Control Module (BCM) 064
Inflatable Restraint Sensing and Diagnostic Module (SDM) 088
Instrument Panel Cluster (IPC) 096
Radio 128
Audio Amplifier 129
Remote Playback Device-CD Changer 130
Digital Audio Broadcast Module (DAB) 136
Digital Radio Receiver 137
Vehicle Communication Interface Module (VCIM) 151
HVAC Control Module 152
Rear Seat Audio Controller 154
Rear Seat Entertainment (RSE) Assembly 154
Driver Door Module (DDM) 160
Front Passenger Door Module (FPDM) 161
Memory Seat Module (MSM 166
RSA/HVAC Control Module 167
Theft Deterrent Control Module 192
There is other modules not listed that can cause problems also, like glow plug controller, Fuel injection control module.

what code did it set?? It was most likely a Uxxxx code

Mine might be the glow plug, I don't have the code number right off hand but I will write it down and post it.

Are you using the correct clear codes command.
There is one that will clear ECM codes only, and one that clears ALL modules (Shift+F11).

Cheers,
Ross

Yes sir, one thing I have done also I switched out my 01 ecm for an 02 ecm.

Can you please get the exact Uxxx number.

Cheers,
Ross

In 'swapping' PCM's--did you also replace the proper VIN number ?

Lyndon.

Can you please get the exact Uxxx number.

Cheers,
Ross

Ross,

Sorry about the delay, the code I get is U1000.
Hope this is really nothing to worry about

In 'swapping' PCM's--did you also replace the proper VIN number ?

Lyndon.
Yes sir I did enter my original 2001 ecm vin, and had to disable my vats at first till I did the vats relearn per instructions from your site.

Joe