Diagnostic Procedure

WARNING: This page is about a different variant/trim than selected.

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.
2. NO: Repair the CAN bus lines. (Refer to TROUBLESHOOTING ).
STEP 2. Scan tool diagnostic trouble code
Check the engine diagnostic trouble code. (Refer to DIAGNOSTIC TROUBLE CODE TABLE ).

Q: Is the DTC set?
1. YES: Perform the relevant troubleshooting.
2. NO: Go to Step 3.
STEP 3. Scan tool data list
Check the following data list. (Refer to DATA LIST REFERENCE TABLE ).
- Item No. 15: Engine speed
- Item No. 16: Engine torque (Driver request value)
Q: Is the check result normal?
1. YES: Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
2. NO: Go to Step 4.
STEP 4. Check whether the DTC is reset.
Q: Is DTC No. U0401 set?
1. YES: Replace the AWC-ECU. (Refer to AWC-ECU ). Then go to Step 5.
2. NO: Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
STEP 5. Check whether the DTC is reset.
Q: Is DTC No. U0401 set?
1. YES: Return to Step 1.
2. NO: This diagnosis is complete.