DTC U0121: Can Time-Out Error (Abs/ASC): Diagnosis
- STEP 1. Scan tool (M.U.T.-IIISE) CAN bus diagnostics.
Use scan tool (M.U.T.-IIISE) to perform the CAN bus diagnosis. (Refer to CAN BUS DIAGNOSIS ).
Q: Is the check result normal?
YES: Go to Step 2.
NO: Repair the CAN bus lines (Refer to CAN BUS DIAGNOSTICS TABLE ).
- STEP 2. Scan tool (M.U.T.-IIISE) diagnostic trouble code.
Check if the ASC-related diagnostic trouble code is set.
Q: Is the ASC-related diagnostic trouble code set?
YES: Carry out the appropriate troubleshooting.
NO: Go to Step 3.
- STEP 3. Scan tool (M.U.T.-IIISE) diagnostic trouble code.
Is diagnostic trouble code No. U0121 set in the other ECU, which communicates with the ASC-ECU via CAN?
Q: Is the diagnostic trouble code set?
YES: Go to Step 4.
NO: Go to Step 5.
- STEP 4. Symptom recheck after erasing diagnostic trouble code.
Q: Is the diagnostic trouble code set?
YES: Replace the ASC-ECU.
NO: Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).
- STEP 5. Symptom recheck after erasing diagnostic trouble code.
Q: Is the diagnostic trouble code set?
YES: Replace the TCM.
NO: Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).