C1082-02

C1082-02-VACUUM PRESSURE SENSOR - PERFORMANCE OR INCORRECT OPERATION





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

- When Monitored:
With the ignition on and engine running for five minutes.

- Set Condition:
When the Anti-Lock Brake Module detects that the vacuum sensor signal does not make sense based on other vehicle conditions. No signal change, signal rapid change, unexpected change.





1. CHECK IF PCM DTCS ARE PRESENT
1. With the scan tool, read the PCM DTCs.

Are there any PCM DTCs present?

Yes

- Perform the appropriate diagnostic procedures. Testing and Inspection.

No

- Go To 2

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

Were any problems found?

Yes

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

No

- Go To 3

3. VACUUM PRESSURE SIGNAL
1. Start the engine.
2. With the scan tool, view and record the vacuum pressure signal with foot off the brake pedal.
3. With the scan tool, view the vacuum pressure signal while pressing the brake pedal several times.
4. Record the highest value.

Without the brake pedal applied, was the vacuum pressure signal -400 mbar (-5.8 psi)

Yes

- Go To 4

No

- Replace the Power Brake Booster. Power Brake Booster - Removal.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

4. CHECK FOR VACUUM PRESSURE SIGNAL CHANGE
1. Turn the ignition on.
2. Remove the Vacuum Pressure Sensor from the Booster.
3. Connect a vacuum pump to the Vacuum Pressure Sensor.
4. Apply vacuum to the Vacuum Pressure Sensor and watch for signal change.

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

Yes

- Go To 5

No

- Replace the Power Brake Booster. Power Brake Booster - Removal.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

5. CHECK BRAKE BOOSTER CHECK VALVE
1. Remove the Brake Booster Check Valve.
2. Apply vacuum to the booster side of the check valve.

Is the Brake Booster Check Valve holding vacuum?

Yes

- Go To 6

No

- Replace the Power Brake Booster. Power Brake Booster - Removal.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

6. CHECK BRAKE BOOSTER
1. Reinstall the Brake Booster Check Valve.
2. Apply vacuum to the Brake Booster.

Is the Brake Booster holding vacuum?

Yes

- Go To 7

No

- Replace the Power Brake Booster. Power Brake Booster - Removal.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

7. (3.6L) ENGINE WITH ELECTRIC VACUUM PUMP
1. Verify vehicle is equipped with a 3.6L engine and an electric vacuum pump.

Is the vehicle is equipped with a 3.6L engine and an electric vacuum pump?

Yes

- Go To 8

No

- Go To 9

8. ELECTRIC VACUUM PUMP (3.6L)
1. Turn the ignition on.
2. With the scan tool, under "Miscellaneous Functions" activate the Electronic Vacuum Pump.

Did the Electric Vacuum Pump run?

Yes

- Go To 9

No

- Replace the Power Brake Booster. Removal.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

9. ANTI-LOCK BRAKE SYSTEM (ABS)
1. Turn the ignition off to the lock position.
2. Perform any Technical Service Bulletins that may apply.
3. Inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
4. Inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals.

Were any problems found?

Yes

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

No

- Replace the Anti-lock Brake System (ABS) Module. Anti-Lock Brake System Module - Removal.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.