Inspection Procedure 1

INSPECTION PROCEDURE 1: Communication between the scan tool and AWC-ECU cannot be established

CAUTION:

- If there is any problem in the CAN bus lines, an incorrect trouble symptom may occur. Prior to this diagnosis, always diagnose the CAN bus lines.
- Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

COMMENTS ON TROUBLE SYMPTOM

CAN bus line, AWC-ECU power supply circuit, or AWC-ECU may have a problem.

PROBABLE CAUSES

- Wrong scan tool wiring harness
- The CAN bus line is defective.
- AWC-ECU power supply circuit malfunction
- Malfunction of AWC-ECU
- ECU malfunction of other system

DIAGNOSTIC PROCEDURE

STEP 1. Scan tool CAN bus diagnostics

Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?

YES Check/repair the AWC-ECU power supply circuit.(Refer to Inspection Procedure 3.)
NO Repair the CAN bus lines. CAN Bus Diagnostics Chart.)