GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Hydraulic Brake Schematics

Connector End View Reference: Hydraulic Brake Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Apply the park brake.
  3. With a scan tool, observe the Park Brake Switch parameter in the Body Control Module data list.

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

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the park brake switch.
  3. Connect a 3A fused jumper wire between the signal circuit of the park brake warning lamp switch and ground.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the Park Brake Switch parameter.

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

Go to Step 5

Go to Step 4

4

Test the signal circuit of the park brake switch for a open circuit. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 6

5

Inspect for poor connections at the harness connector of the park brake switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 7

6

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 8

7

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

Did you complete the repair?

Go to Step 9

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8

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 9

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9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2