GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Monte Carlo 🢒 Engine 🢒 Engine Electrical 🢒 DTC B1508

Circuit Description

The BCM monitors the load control circuit for shorts to ground and shorts to voltage.

The circuit starts at the BCM and travels to the IP fuse panel where the circuit splits to supply power for the heated seat switch and HVAC control head for the rear defog relay driver.

Conditions for Running the DTC
    • The Voltage to the BCM must be between 9.0 and 16.0 volts.
    • The ignition must be in the ON position.
    • The Load Shed system must be active
    • This DTC shall not set during BCM programing and configuration changes.
    • This DTC shall not set if any communication codes are set.

Conditions for Setting the DTC

The voltage of the load control circuit, at the module, shall be greater than 8 volts for 1/2 second while the output is inactive.

Action Taken When the DTC Sets

The BCM sets a DTC and disables the following State of Health (SOH) DTCs:

    • DTC U1096
    • DTC U1255
    • DTC U1300
    • DTC U1301

The BCM illuminates the SVS indicator

Conditions for Clearing the MIL/DTC
    • The Load Shed system in not in an active state.
    • The voltage of the load control circuit at the module shall be less than 8 volts for 1/2 second while the output is inactive.
    • A history DTC clears after 100 malfunction free ignition cycles.
    • The BCM receives the clear code command from the scan tool.

Step

Action

Yes

No

Schematic Reference: Body Control System Schematics in Body Controls

1

Did you perform the Diagnostic System Check for Engine Electrical?

Go to Step 2

Go to Diagnostic System Check - Engine Electrical

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, monitor the DTC Information for DTC B1508 in the BCM.

Does the scan tool indicate that DTC B1508 is current?

Go to Step 3

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

3

Test the load control circuit of the BCM for a short to voltage. 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 BCM. 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 procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Controls.

Replace the BCM. Refer to Body Control Module Replacement in Body Controls.

Did you complete the replacement?

Go to Step 6

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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