C121E
C121E-BRAKE PRESSURE SENSOR COMPARATIVE PERFORMANCE
For a complete wiring diagram Refer to Diagram/Electrical
- When Monitored:
With the ignition on.
- Set Condition:
When the Anti-Lock Brake Module indicates that the Brake Pressure Sensor Signal is irrational.
Diagnostic Test
1. CHECK FOR A DTC C121E-BRAKE PRESSURE SENSOR COMPARATIVE PERFORMANCE
Turn the ignition on.
With the scan tool, read and record DTCs.
With the scan tool, read and record Freeze Frame information.
With the scan tool, erase DTCs.
Start the engine.
Depress and release the brake pedal.
With the scan tool, read and record DTCs.
Does the scan tool display: C121E-BRAKE PRESSURE SENSOR COMPARATIVE PERFORMANCE?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition
- Perform ABS VERIFICATION TEST - VER 1. Verification Tests
2. CHECK BRAKE SWITCH
With the scan tool look at the Brake Switch Signal.
Apply the brakes on and off while checking for a Brake Switch Signal change.
Did the Brake Switch Signal change?
Yes
- Go To 3
No
- Repair as needed.
3. CHECK BRAKE PRESSURE SENSOR
With the scan tool look at Pressure Sensor Signal and the Brake Switch Signal.
With the brakes not applied the Pressure Sensor should read ± 15 bar.
Apply the brakes the Pressure Sensor should read above 15 bar.
Did Brake Pressure Sensor increase above 15 bar?
Yes
- Replace the Integrated Control Unit.
- Perform ABS VERIFICATION TEST - VER 1. Verification Tests
No
- Go To 4
4. CHECK FOR AIR IN BRAKE SYSTEM
NOTE: Before continuing the brake system must be bled to verify there is no air in the brake system.
Turn ignition off.
Bleed brake system.
Was there any air in the brake system?
Yes
- Repair as needed.
- Perform ABS VERIFICATION TEST - VER 1. Verification Tests
No
- Replace the Integrated Control Unit.
- Perform ABS VERIFICATION TEST - VER 1. Verification Tests