Diagnostic Test
- CHECK FOR A DTC C1221-BRAKE PRESSURE SENSOR/ACCEL PEDAL POSITION SENSOR CORRELATION
- 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: C1221-BRAKE PRESSURE SENSOR/ACCEL PEDAL POSITION SENSOR CORRELATION?
Yes
- Go To 2
No
- The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
- Perform ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
- 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.
- 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 (218 psi).
- Apply the brakes the Pressure Sensor should read above 15 bar (218 psi).
Did Brake Pressure Sensor increase above 15 bar (218 psi)?
Yes
- Replace the Integrated Control Unit in accordance with the Service Information.
- Perform ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
No
- Go To 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 ABS VERIFICATION TEST .
No
- Replace the Integrated Control Unit in accordance with the Service Information.
- Perform ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .