Retained Accessory Power System: Overview Chevrolet Silverado 2500

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 2) - 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.
2. 4) - This step is checking for DTCs in the BCM.
3. 5) - This step is checking for a malfunctioning BCM.
4. 6) - This step is checking for RAP specific DTCs.

Scheme 40

Scheme 41

Scheme 42

The numbers below refer to the step numbers on the diagnostic table.

1. 2) - Listen for an audible click when the RAP#1 relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 3) - This step tests for voltage at the coil side of the RAP#1 relay. The RAP#1 fuse in the Fuse Block Underhood, supplies power to the coil side of the RAP#1 relay.
3. 4) - This step verifies that the Body Control Module (BCM) is providing ground to the RAP#1 relay.
4. 5) - This step tests if ground is constantly being applied to the RAP#1 relay.

Scheme 43

Scheme 44

The numbers below refer to the step numbers on the diagnostic table.

1. 2) - Listen for an audible click when the RAP#1 relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 3) - This step verifies that the Body Control Module (BCM) is providing ground to the RAP#1 relay.