GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The park brake switch monitors if the park brake is engaged. When the body control module (BCM) sees the park brake switch input grounded, it sends a serial data message to the instrument panel cluster (IPC) requesting illumination of the red brake indicator.

Conditions for Running the DTC

The vehicle speed is greater than 8 km/h (5 mph).

Conditions for Setting the DTC

The BCM detects a ground on the park brake switch signal circuit for longer than 2 seconds.

Action Taken When the DTC Sets

The red brake warning indicator turns on.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
    • The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Step

Action

Yes

No

Schematic Reference: Brake Warning System Schematics

Connector End View Reference: Computer/Integrating Systems Connector End Views in Computer/Integrating Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Park Brake Switch parameter in the brake control module (BCM) data list.

Does the scan tool indicate that the Park Brake Switch parameter is OK?

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

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the park brake switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Park Brake Switch parameter.

Does the scan tool indicate that the Park Brake Switch parameter is OK?

Go to Step 5

Go to Step 4

4

Test the signal circuit of the park brake switch 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 7

Go to Step 6

5

Replace the park brake switch. Refer to Parking Brake Indicator Switch Replacement .

Did you complete the repair?

Go to Step 7

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6

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems.

Did you complete the repair?

Go to Step 7

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7

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2