STEP 1. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
STEP 2. Using scan tool (M.U.T.-IIISE), check other system DTC
STEP 3. Check whether the DTC is set.
STEP 4. Using scan tool (M.U.T.-IIISE), check data list
STEP 5. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Turn the ignition switch to the "ON" position.
Is DTC C121C set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). If the trouble symptom is resolved, an intermittent malfunction such as poorly engaged connector(s) or wiring harness is suspected (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).