U0101 GMC Lost Communication With Transmission Control Module

Possible causes
– Faulty Transmission Control Module (TCM)
– TCM harness is open or shorted
– TCM circuit poor electrical connection
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
U0101 GMC Description
Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. The supervision time-out period is 250 ms. Each message contains the identification number of the transmitter module.
GMC Technical Service Bulletins for U0101 code
2007 GMC SIERRA ENGINE AND ENGINE COOLING:ENGINE
2007 GMC SIERRA POWER TRAIN:AUTOMATIC TRANSMISSION
2007 GMC SIERRA POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM, PCM)
2007 GMC SIERRA LATCHES/LOCKS/LINKAGES:DOORS:LATCH
2007 GMC SIERRA DIGITAL INSTRUMENT PANEL
2007 GMC YUKON ENGINE AND ENGINE COOLING:ENGINE
2007 GMC YUKON POWER TRAIN:AUTOMATIC TRANSMISSION
2007 GMC YUKON POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM, PCM)
2007 GMC YUKON LATCHES/LOCKS/LINKAGES:DOORS:LATCH
2007 GMC YUKON DIGITAL INSTRUMENT PANEL