C121E - Brake Pressure Sensor Comparative Performance
For a complete wiring diagram, refer to appropriate Wiring Diagram.
- >>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 |
|---|
| ECU INTERNAL FAILURE |
| HCU INTERNAL FAILURE |
Test Step 1 - Test for DTC C121E - Brake Pressure Sensor Comparative Performance
NOTE:
This DTC must be active for the results of this test to be valid.
- Turn the ignition ON.
- With the scan tool, read and record the DTCs.
- With the scan tool, read and record the Environmental Data to help identify the conditions in which the DTC was set.
- With the scan tool, erase the DTCs.
- Start the engine.
- Slowly press and release the brake pedal.
- With the scan tool, read and record the DTCs.
Does the scan tool display C121E - Brake Pressure Sensor Comparative Performance?
Yes
- Go to Test Step 2
No
- Perform the ABS Intermittent Condition Test. Refer to ABS INTERMITTENT CONDITION TEST (2009 - 2011) or ABS INTERMITTENT CONDITION (2012 & UP) .
Test Step 2 - HCU/ECU Isolation
- Turn the ignition OFF.
- Separate the ECU from the HCU.
- Turn the ignition ON.
- With the scan tool, monitor the brake pressure.
Does the scan tool display brake pressure more than 218 bar (3162 psi)?
Yes
- Replace the HCU. Refer to REMOVAL AND INSTALLATION .
- Perform ABS Verification Test. Refer to ABS VERIFICATION TEST (2009 - 2011) or ABS VERIFICATION TEST (2012 & UP) .
No
- Replace the ECU. Refer to REMOVAL AND INSTALLATION . Perform ABS Verification Test. Refer to ABS VERIFICATION TEST (2009 - 2011) or ABS VERIFICATION TEST (2012 & UP) .