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DTC U0121: ASC CAN Timeout
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be stored. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
AWC-ECU communicates with the ASC-ECU via the CAN bus lines.
 
 
DTC SET CONDITION
This DTC is stored when the abnormality below is detected:
  • The signal sent from the ASC-ECU cannot be received for a certain period.
 
 
PROBABLE CAUSES
  • Malfunction of the CAN bus line
  • Malfunction of ASC-ECU power supply circuit system
  • Malfunction of ASC-ECU
  • Malfunction of AWC-ECU

 
 
DIAGNOSTIC PROCEDURE
STEP 1. Scan tool (M.U.T.-III) CAN bus diagnostics.
Use scan tool (M.U.T.-III) to perform the CAN bus diagnosis.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - Diagnosis, Can Bus Diagnostics Table ).
 
STEP 2. Scan tool (M.U.T.-III) other system DTC.
Check the ASC DTC (Refer to GROUP 35C - Diagnosis, Diagnostic Trouble Code Chart ).
Is the DTC stored?
Perform the relevant troubleshooting.
Go to Step 3.
 
STEP 3. Check whether the DTC is stored again.
Is DTC No.U0121 stored?
Replace the AWC-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 DTC is stored again.
Is DTC No.U0121 stored?
Return to Step 1.
This diagnosis is complete.