C0021

C0021-BRAKE BOOSTER PERFORMANCE





For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.

- When Monitored:
With the ignition on.

- Set Condition:
When the Vacuum Pressure Sensor indicates a failure in the Vacuum Booster.





1. CHECK FOR A DTC C0021-BRAKE BOOSTER PERFORMANCE

NOTE: This DTC must be active for the results of this test to be valid.

1. Turn the ignition on.
2. With the scan tool, read and record the DTCs.
3. With the scan tool, read and record the Environmental Data to help identify the conditions in which the DTC was set.
4. With the scan tool, erase the DTCs.
5. Start the engine.

NOTE: Attempt to operate the vehicle under conditions similar to which the DTC was set. It may be necessary to test drive the vehicle within the DTC monitoring and set conditions in order for this DTC to set.

6. Press and release the brake pedal.
7. With the scan tool, read and record the DTCs.

Does the scan tool display: C0021-BRAKE BOOSTER PERFORMANCE?

Yes

- Go To 2

No

- Perform the ABS INTERMITTENT CONDITION TEST ABS Intermittent Condition Test.

2. CHECK FOR PINCHED VACUUM SUPPLY LINE
1. Turn the ignition off.
2. Check the vacuum supply line to brake booster for a pinched or kinked hose.

Were any problems found?

Yes

- Repair as necessary.
- Perform ABS VERIFICATION TEST ABS Verification Test.

No

- Go To 3

3. CHECK FOR VACUUM PRESSURE SIGNAL CHANGE
1. Turn the ignition off.
2. Connect a vacuum pump to the brake booster.
3. Apply vacuum to the booster and watch for a signal change

Is the voltage signal changing on the scan tool as the vacuum is being applied?

Yes

- Go To 4

No

- Replace the Vacuum Pressure Sensor.
- Perform ABS VERIFICATION TEST ABS Verification Test.

4. CHECK BRAKE BOOSTER
1. Check that the brake booster and check valve are operating properly.

Is the brake booster and check valve holding vacuum?

Yes

- Replace the Anti-Lock Brake Module.
- Perform ABS VERIFICATION TEST ABS Verification Test.

No

- Repair as necessary.
- Perform ABS VERIFICATION TEST ABS Verification Test.