GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The BCM monitors the condition of the load B+ supply circuits. When the BCM has 9-16 volts from the CLSTR/BCM fuse, the BCM tests to verify voltage and grounds are present for the BCM outputs.

The battery feed circuit, from the HTD SEAT fuse, provides power for the following items:

    • Heated seats
    • RAP Relay coil
    • Rear Defogger Relay coil

The battery feed circuit, from the DR LK fuse to the BCM, provides power for the following items:

    • Door locks
    • Trunk release motor

Conditions for Running the DTC

The voltage on the battery feed circuit, from the CLSTR/BCM fuse to the BCM must be between 9-16 volts.

Conditions for Setting the DTC

The BCM must detect:

    • the B+ supply circuit for load and RAP functions is less than 1 volt
    • the B+ supply circuit for the lock and trunk release functions is less than 1 volt
    • the above conditions last for more than 300 milliseconds

Action Taken When the DTC Sets

    • The lock and release functions may not operate.
    • The defrost functions for the rear window and the exterior mirrors may not operate.
    • The heated seats may not operate.
    • The BCM stores DTC B1339 in memory.

Conditions for Clearing the DTC

    • A current DTC clears when the malfunction is no longer present.
    • A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Step

Action

Yes

No

Schematic Reference: Body Control System Schematics

1

Did you perform the Diagnostic System Check for the affected system?

Go to Step 2

Go to the Diagnostic System Check for the affected system

2

  1. Install a scan tool.
  2. With a scan tool, observe the Loads Battery Fd parameter and the Doors Battery Fd parameter in the Body Control Module input data list.

Does the scan tool display Active for both parameters?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Test the battery circuit that does not display Active in the previous step for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Inspect for poor connections at the harness connector of the Body Control Module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

Important: Perform the Set up New Body Control Module procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration .

Replace the Body Control Module. Refer to Body Control Module Replacement .

Did you complete the repair?

Go to Step 6

--

6

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK