I have a 2007 GMC Yukon. started it up and left home, immediatly had service 4 wheel drive light, abs light, low tire psi light and shifting weird. i pulled over put vehicle in park shut it off and attempted to start it again to see if it would go away and it wouldn't turn over or even attempt to start. i know it's not a battery problem and this is the second time this has happened.gmc had to reset or reprogram it the first time. any ideas what is causing this? i do have an aftermarket stereo. GMC told me the first time thats what caused it most likely but all my audio buds think it's something else and GMC is blaming them.
Ok supper Dave , let's get this stright , when you turn the key to start the vehicle , what happens ? The starter spins the engine or doesn't spin the engine ? This would be a no crank no start condition . if the engine does spin an doesn't start an run this is a crank no start condition . Now which is it ? The factory radio is hooked to the serial data communication network , did you or who ever installed the aftermarket radio use a interface module ? Are you familiar with the electronics on this vehicle ? BCM - body control module , low current inputs from the ignition switch which determine what mode to put the vehicle in ?
Case 4 Data Bus Issues
The body control system consists of the body control module (BCM), communications, and various input and outputs. Some inputs, outputs and messages require other modules to interact with the BCM. The BCM also has discrete input and output terminals to control the vehicle's body functions. The BCM is wired to the GMLAN high speed serial data buss and the GMLAN low speed serial data buss and acts as a gateway between them. If the BCM does not communicate the vehicle will not start due to the inability of the engine control module (ECM)/powertrain control module (PCM) and theft deterrent module (TDM) to communicate without the BCM providing the gateway function.
Power Mode Master
This vehicles body control module (BCM) functions as the power mode master (PMM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination the power mode that will be sent over the serial data circuits to the other modules that need this information, and so the PMM will activate relays and other direct outputs of the PMM as needed. Refer to Power Mode Description and Operation for a complete description of power mode functions.
Sorry but I am a GM Tech . have been for over thirty years , Cadillac , Buick an Chevy .audio buds think it's something else. Your audio buds don't have a clue ? When change something you better well know what your messing with. .
SOURCE: Instrument cluster says " Service 4 Wheel Drive". No 4 wheel drive while this is on.
Two possibilites:
Have you been thru a car wash lately?
Also,
There is a sensor in the trans that senses what gear mode you're in...it either is working or it isn't....
are you still under warranty??
k
SOURCE: wont shift back from 4x4 low, to 2x2
put the truck shifter from park to neutral then shift 4x4 button into 2whl Or Auto which ever you prefer. note when always shifting into low 4x4 or out the transmission MUST BE in neutral
SOURCE: gmc yukon has the abs & parking brake light
you have to fix the problem with ur brakes- first check the wiring ,connectors and connection clips to the abs sensors and modulator if looks ok than have truck scanned some auto stores such as auto zone / advanced auto do it for free the code will give u a start point towards fixing ur problem--visual inspection of brakes doesnt always show problem
SOURCE: My 2002 Gmc Envoy is stuck in 4wheel low. I
Before you spend a ton of money check the switch in the dash. Sometimes the metal just doesn't connect.
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