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 if the AWC diagnostic trouble code No. U1003 is set. (Refer to DIAGNOSTIC TROUBLE CODE CHART .)

Q: Is the DTC set?
1. YES: Perform the relevant troubleshooting.
2. NO: Go to STEP 3 below.
STEP 3. 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 4 below.
STEP 4. Scan tool service data
Check the service data below. (Refer to WHEEL SPEED SENSOR .)
- Item No. 22: FL wheel speed sensor < FL >
- Item No. 23: FL wheel speed sensor < FR >
- Item No. 24: FL wheel speed sensor < RL >
- Item No. 25: FL wheel speed sensor < RR >
Q: Is the check result normal?
1. YES: Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .)
2. NO: Go to STEP 5 below.
STEP 5. Check whether the DTC is reset.
Q: Is DTC No. U1427 set?
1. YES: Replace the AWC-ECU. (Refer to AWC-ECU .) Then go to STEP 6 below.
2. NO: Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .)
STEP 6. Check whether the DTC is reset.
Q: Is DTC No. U1415 set?
1. YES: Return to Step 1.
2. NO: This diagnosis is complete.