Code No. U0121: CAN Time-out Error (ASC)


DIAGNOSTIC FUNCTION


The CVT-ECU determines that the system is defective if the ECU can receive no CAN communication information from the ASC-ECU.

JUDGEMENT CRITERIA


No information is received from the ASC-ECU for 2.5 seconds.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use M.U.T.-III to perform the CAN bus diagnosis.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting, Diagnosis Code Chart ).

STEP 2. M.U.T.-III diagnosis code.
Check if the ASC-related diagnosis code is stored.

Q. Is the ASC-related diagnosis code stored?
Carry out the appropriate troubleshooting. (Refer to GROUP 35C - Troubleshooting, Diagnosis Code Procedures ).
Go to Step 3.

STEP 3. M.U.T.-III diagnosis code.
Is diagnosis code No. U0121 stored in the other ECU, which communicates with the ASC-ECU via CAN?

Q. Is the diagnosis code stored?
Go to Step 4.
Go to Step 5.

STEP 4. Symptom recheck after erasing diagnosis code.

Q. Is the diagnosis code stored?
Replace ASC-ECU {Refer to GROUP 35C - Hydraulic Unit (integrated with ASC-ECU) }.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions).

STEP 5. Symptom recheck after erasing diagnosis code.

Q. Is the diagnosis code stored?
Replace CVT-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions).