DTC U0121: CAN Time-out Error (ABS)
DIAGNOSTIC FUNCTION
TCM determines that malfunction is present if the periodic communication data sent from the ABS-ECU via CAN bus lines is abnormal.
JUDGMENT CRITERIA
TCM cannot receive the periodic communication data from ABS-ECU.
PROBABLE CAUSES
Malfunction of the CAN bus
ABS-ECU malfunction
Malfunction of TCM
DIAGNOSTIC PROCEDURE
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
Use scan tool MB991958 to perform the CAN bus diagnosis.
Is the check result normal?
Go to Step 2
.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting, Diagnostic Trouble Code Chart
).
STEP 2. Scan tool diagnostic trouble code
Check if the ABS-related diagnostic trouble code is set.
Is the ABS-related diagnostic trouble code set?
Carry out the appropriate troubleshooting.
Go to Step 3
.
STEP 3. Symptom recheck after erasing diagnostic trouble code
Is the check result normal?
Intermittent malfunction
Replace TCM.
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Go to Step 2
.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting, Diagnostic Trouble Code Chart ).Carry out the appropriate troubleshooting.Go to Step 3.Intermittent malfunctionReplace TCM.