C1221-BRAKE PRESSURE SENSOR/ACCEL PEDAL POSITION SENSOR CORRELATION
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 output signal is not plausible.
| Possible Causes |
| AIR IN BRAKE SYSTEM / WORN MECHANICAL COMPONENTS |
| BRAKE SWITCH SIGNAL OPEN |
| BRAKE PRESSURE SENSOR |
| INTEGRATED CONTROL MODULE |
Diagnostic Test
1. CHECK FOR A DTC C1221-BRAKE PRESSURE SENSOR/ACCEL PEDAL POSITION SENSOR CORRELATIONTurn 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: C1221-BRAKE PRESSURE SENSOR/ACCEL PEDAL POSITION SENSOR CORRELATION?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION diagnostic procedure.
- Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
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 in accordance with the Service Information.
- Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
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.
Check worn mechanical components.
Was there any air in the brake system or worn mechanical components?
Yes
- Repair as needed.
- Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
No
- Replace the Integrated Control Unit in accordance with the Service Information.
- Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).