Express 1500 RWD V8-5.3L VIN T (2004)
Steps 6-9
The numbers below refer to the step numbers on the diagnostic table.
1. This step verifies that the retained accessory power (RAP) power mode is malfunctioning by checking functions enabled by the body control
module (BCM).
3. The BCM sends class 2 messages to other control modules via the serial data link, allowing them to operate in RAP power mode. Lack of
communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit.
The specified procedure will determine the particular condition.
5. This step checks for diagnostic trouble codes (DTCs) in the BCM.
6. The presence of DTCs which begin with "U" indicate that a control module is not communicating. Diagnose DTCs that begin with "U" before you
diagnose any other DTCs.
