Diagnostic Procedure

STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.

Q: Is the check result normal?
1. YES: Go to STEP 2 below.
2. NO: Repair the CAN bus lines. (Refer to TROUBLESHOOTING .)
STEP 2. Scan tool service data
Item No. 11: Steering wheel sensor (refer to WHEEL SPEED SENSOR .)

Q: Is the check result normal?
1. YES: Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .)
2. NO: Replace the steering wheel sensor. (Refer to STEERING WHEEL SENSOR .) Then go to STEP 3 below.
STEP 3. Check whether the DTC is reset.
Q: Is DTC No. U0428 set?
1. YES: Replace the AWC-ECU. (Refer to AWC-ECU .) Then go to STEP 4 below.
2. NO: Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .)
STEP 4. Check whether the DTC is reset.
Q: Is DTC No. U0428 set?
1. YES: Return to Step 1.
2. NO: This diagnosis is complete.