Code No.U0121: ABS/ASC CAN Timeout


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION



DIAGNOSIS CODE SET CONDITION




  • The signal sent from the ABS/ASC-ECU cannot be received for a certain period.

PROBABLE CAUSES



  • Malfunction of the CAN bus line
  • Malfunction of power supply circuit system (ABS/ASC-ECU)
  • Malfunction of ECU (ABS/ASC-ECU)
  • Malfunction of 4WD-ECU

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 ).

STEP 2. M.U.T.-III other system diagnosis code.
Check the ABS diagnosis code (Refer to GROUP 35B - Troubleshooting ) <Vehicles with ABS> or the ASC diagnosis code (Refer to GROUP 35C - Troubleshooting ) <Vehicles with ASC>.

Q. Is the diagnosis code set?
Perform the relevant troubleshooting.
Go to Step 3.

STEP 3. Check whether the diagnosis code is reset.

Q. Is diagnosis code No.U0121 set?
Replace the 4WD-ECU (Refer to ). Then go to Step 4.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 4. Check whether the diagnosis code is reset.

Q. Is diagnosis code No.U0121 set?
Return to Step 1.
This diagnosis is complete.