Diagnostic Procedure

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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 ASC 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 diagnostic trouble code
Check if the ACD diagnostic trouble code No. C123C, C1242 is set. (Refer to DIAGNOSTIC TROUBLE CODE TABLE ).

Q: Is the check result normal?
1. YES: Perform the relevant troubleshooting.
2. NO: Go to Step 4.
STEP 4. Scan tool data list
Check the data list below. (Refer to DATA LIST REFERENCE TABLE ).
- Item No. 26: Yaw rate sensor
- Item No. 29: Lateral G sensor
- Item No. 31: Longitudinal G sensor
Q: Is the check result normal?
1. YES: Go to Step 5.
2. NO: Replace the G and yaw rate sensor. (Refer to G AND YAW RATE SENSOR ). Then go to Step 6.
STEP 5. Check whether the DTC is reset.
Q: Is DTC No. U1428 set?
1. YES: Replace the AWC-ECU. (Refer to AWC-ECU ). Then go to Step 6.
2. NO: Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
STEP 6. Check whether the DTC is reset.
Q: Is DTC No. U1428 set?
1. YES: Return to Step 1.
2. NO: This diagnosis is complete.