C 3500 Truck 2WD V8-6.0L VIN U (2001)
Body Control Module: Symptom Related Diagnostic Procedures
POWER MODE MISMATCH
CIRCUIT DESCRIPTION
Normal vehicle class 2 communications and module operations will not begin until the system power mode has been identified. Discrete wires from
the ignition switch contacts are monitored by the power mode master (PMM) module in order to determine the correct power mode. The PMM
communicates the system power mode to all class 2 modules on the class 2 serial data line. Refer to Body Control System Description and Operation
to identify which module is the PMM and the applicable power mode look up table.
TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
