For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
SCHEMATIC REFERENCE: Brake Warning System Schematics
1 | Did you perform the Hydraulic Brake Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Hydraulic Brakes
2 | Inspect the brake fluid level. Is the brake fluid level OK? | Go to Step 3 | Go to Brake Fluid Leak
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 BCM Inputs data list.

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

Go to Step 4

Go to Step 5

4 | With a scan tool, observe the Brake Warning Lamp parameter in the EBCM Inputs data list. Does the scan tool indicate that the Brake Warning Lamp parameter is Off? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 6
5 |

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 Off?

Go to Step 9

Go to Step 7

6 |

1. Turn OFF the ignition.
2. Disconnect the brake fluid level switch.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool, observe the Brake Warning Lamp parameter.

Does the scan tool indicate that the Brake Warning Lamp parameter is Off?

Go to Step 10

Go to Step 8

7 | 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 17 | Go to Step 11
8 | Test the signal circuit of the brake fluid level 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 17 | Go to Step 12
9 | 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 in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 13
10 | Inspect for poor connections at the harness connector of the brake fluid level switch. 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 17 | Go to Step 14
11 | Inspect for poor connections at the harness connector of the body control module. 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 17 | Go to Step 15
12 | Inspect for poor connections at the harness connector of the electronic brake control module (EBCM). 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 17 | Go to Step 16
13 | Replace the park brake switch. Refer to Parking Brake Indicator Switch Replacement in Park Brake. Did you complete the repair? | Go to Step 17 | --
14 | Replace the brake fluid level switch. Refer to Brake Fluid Level Indicator Switch Replacement . Did you complete the repair? | Go to Step 17 | --
15 | Replace the body control module. Refer to Body Control Module Replacement in Body Control System. Did you complete the repair? | Go to Step 17 | --
16 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement in Antilock Brake System. Did you complete the repair? | Go to Step 17 | --
17 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2