Code No. U0121: CAN time-out error (ABS/ASC)


DIAGNOSTIC FUNCTION


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

JUDGEMENT CRITERIA


No information is received from the ABS/ASC-ECU for 0.5 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.

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

Q. Is the ABS/ASC-related diagnosis code set?
Carry out the appropriate troubleshooting.
Go to Step 3

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

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

STEP 4. Symptom recheck after erasing diagnosis code

Q. Is the diagnosis code set?
Replace ABS/ASC-ECU.
Intermittent malfunction.

STEP 5. Symptom recheck after erasing diagnosis code

Q. Is the diagnosis code set?
Replace CVT-ECU.
Intermittent malfunction.