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.
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: The diagnostic trouble code is set.
1. YES: Perform the relevant troubleshooting.
2. NO: Go to Step 3.
STEP 3. ASC-ECU connector, G and yaw rate sensor connector, AWC-ECU connector, intermediate connector, J/C (7) check: A-05, C-38, C-46, C-47, C-50
Q: Is the check result normal?
1. YES: Go to Step 4.
2. NO: Repair the defective connector. Then go to Step 7.
STEP 4. Check the wiring harness between C-46 AWC-ECU connector terminal No. 9, 10 and C-38 G and yaw rate sensor connector terminal No. 2, 3, and between C-46 AWC-ECU connector terminal No. 9, 10 and A-05 ASC-ECU connector terminal No. 18, 19.
Check the wiring harness for open and short circuit (to ground, to power supply, or line-to-line).

Q: Is the check result normal?
1. YES: Go to Step 5.
2. NO: Repair the wiring harness. Then go to Step 7.
STEP 5. Scan tool service data
Check the following service data. (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 6.
  2. NO: Replace the G and yaw rate sensor. (Refer to G AND YAW RATE SENSOR .) Then go to Step 6.
STEP 6. Check whether the diagnostic trouble code is reset.
Q: Is DTC No. U1003 set?
1. YES: Replace the AWC-ECU. (Refer to AWC-ECU .) Then go to Step 7.
2. NO: Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .)
STEP 7. Check whether the DTC is reset.
Q: Is DTC No. U1003 set?
1. YES: Return to Step 1.
2. NO: This diagnosis is complete.