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 diagnostic trouble code
Check the ASC diagnostic trouble code. (Refer to TROUBLESHOOTING .)

Q: Is the DTC set?
1. YES: Perform the relevant troubleshooting.
2. NO: Go to STEP 3 below.
STEP 3. Scan tool service data
Item No. 38: Master cylinder pressure 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: Go to STEP 4 below.
STEP 4. Check whether the DTC is reset.
Q: Is DTC No. U1426 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. U1415 set?
1. YES: Return to Step 1.
2. NO: This diagnosis is complete.