GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Brake Warning System 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 in Vehicle DTC Information

2

Check the fluid level in the master cylinder brake fluid reservoir.

Is the brake fluid level OK?

Go to Step 3

Go to Master Cylinder Reservoir Filling

3

  1. Turn ON the ignition, with the engine OFF.
  2. Release 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 Released?

Go to Step 6

Go to Step 4

4

  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 Released?

Go to Step 11

Go to Step 5

5

Test the park brake switch signal 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 13

Go to Step 12

6

With a scan tool, observe the Brake Fluid Level Switch parameter in the instrument panel data list.

Does the scan tool indicate that the Brake Fluid Level Sensor parameter is OFF?

Go to Step 10

Go to Step 7

7

Disconnect the brake fluid level sensor harness connector.

Does the scan tool indicate that the Brake Fluid Level Switch parameter is OFF?

Go to Step 9

Go to Step 8

8

Test the brake fluid level signal 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 13

Go to Step 10

9

Replace the brake fluid level sensor. Refer to Brake Fluid Level Indicator Switch Replacement .

Did you complete the replacement?

Go to Step 13

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10

Replace the instrument panel cluster (IPC). Refer to Control Module References in Computer/Integrating Systems.

Did you complete the replacement?

Go to Step 13

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11

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

Did you complete the repair?

Go to Step 13

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12

Replace the body control module (BCM). Refer to Control Module References in Computer/Integrating Systems.

Did you complete the replacement?

Go to Step 13

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13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2