Power Mode Mismatch

Power Mode Mismatch

Circuit Description

The body control module (BCM) is the power mode master responsible for sending the power mode message on the data buses. The BCM monitors Ignition 1 (Run/Crank) and Ignition 2 (Acc/Run) signals from the ignition switch, and the engine run flag (ERF) in order to determine the present power mode. Refer to Body Control System Description and Operation for the applicable power mode look up table.

Test Description

Step 1 - Step 8:

Step 9 - Step 14:

The numbers below refer to the step numbers on the diagnostic table.
6. This step tests for battery voltage on the signal circuits that are not required.
7. This step tests for no battery voltage on the required signal circuits.
8. If any ignition switch parameters that should be inactive in the present ignition switch position are active, 2 ignition switch signal circuits may be shorted together.
9. This step eliminates open circuits as the cause of the malfunction.