Circuit Description
In order to release the parking brake, the pump motor must supply fluid pressure to the actuator. When this pressure overcomes the spring tension inside of the actuator, the actuator piston moves, releasing the parking brake. The park brake pressure sensor monitors the fluid pressure whenever the ignition is ON.
Diagnostic Aids
Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Park Brake System Schematics | |||
1 | Did you perform the Parking Brake Diagnostic System Check? | Go to Step 2 | |
2 |
Does the parking brake pump motor turn OFF? | Go to Diagnostic Aids | Go to Step 3 |
3 | Disconnect the park brake pump motor relay harness connector. Does the parking brake pump motor turn OFF? | Go to Step 5 | Go to Step 4 |
4 | Repair the short to voltage in the park brake motor supply voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
5 | Connect a test lamp between the park brake motor relay control circuit and a good ground. Does the test lamp illuminate? | Go to Step 6 | Go to Step 7 |
6 |
Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
7 | Replace the park brake pump motor relay. Refer to Park Brake Pump Relay Replacement . Did you complete the replacement? | Go to Step 9 | -- |
8 | Replace the PBCM. Refer to Park Brake Control Module Replacement . Did you complete the replacement? | Go to Step 9 | -- |
9 | Apply the parking brake. Does the parking brake pump motor turn OFF? | System OK | Go to Step 3 |
