C121E–BRAKE PRESSURE SENSOR COMPARATIVE PERFORMANCE
For a complete wiring diagram Refer to Section 8W
- When Monitored:
With the ignition on.
- Set Condition:
When the Anti-Lock Brake Module indicates that the Brake Pressure Sensor Signal is out of range.
| Possible Causes |
| AIR IN BRAKE SYSTEM/WORN MECHANICAL COMPONENTS |
| ECU INTERNAL FAILURE |
| ICU INTERNAL FAILURE |
Diagnostic Test
1.CHECK FOR A DTC C121E–BRAKE PRESSURE SENSOR COMPARATIVE PERFORMANCENOTE: This DTC must be active for the results of this test to be valid.
Does the scan tool display: C121E–BRAKE PRESSURE SENSOR COMPARATIVE PERFORMANCE?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION diagnostic procedure.
- Refer to the ABS-INTERMITTENT CONDITION TEST. (Refer to 5 - BRAKES - DIAGNOSIS AND TESTING)
2.RECHECK FOR A DTC C121E–BRAKE PRESSURE SENSOR COMPARATIVE PERFORMANCE
Does the scan tool display: C121E–BRAKE PRESSURE SENSOR COMPARATIVE PERFORMANCE?
Yes
- Go To 3
- Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
No
- Test complete
3.HCU/ECU ISOLATION
Does the scan tool display brake pressure above 200 psi?
Yes
- Replace the HCU in accordance with the Service Information.
- Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
No
- Replace the ECU in accordance with the Service Information.
- Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).