GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The systems under controlled power are supplied voltage through the controlled power relay. The CONTROLLED POWER Relay Coil Control circuit is grounded whenever the body control module (BCM) is awake, and for 15 minutes after the ignition switch is turned to the LOCK position. After 15 minutes elapse, the battery positive voltage output circuit turns ON. The battery positive voltage output can supply up to 2 amps for up to 3 days. If the BCM detects that more than 2 amps are needed, the BCM wakes up and grounds the CONTROLLED POWER Relay Coil Control circuit.

The BCM measures the voltage at the battery positive voltage output every 300 ms while the BCM is in low power mode.

Conditions for Setting the DTC

The battery positive voltage output circuit is grounded after 2 consecutive monitoring cycles.

Action Taken When the DTC Sets

The BCM turns the CONTROLLED POWER Relay Coil Control circuit OFF until the state of the ignition changes or the BCM wakes up.

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 Module Schematics

1

Did you perform the Diagnostic System Check for the system exhibiting the symptom?

Go to Step 2

Go to Control Module References for the applicable Diagnostic System Check for the system exhibiting the symptom

2

  1. Turn the ignition to the OFF position.
  2. Disconnect the BCM.
  3. Remove the PZM fuse.
  4. Test the BCM battery positive voltage output circuit for a short to ground refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 5

Go to Step 3

3

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

Did you find and correct the condition?

Go to Step 5

Go to Step 4

4

Replace the BCM. Refer to Body Control Module Replacement.

Did you complete the repair?

Go to Step 5

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5

  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