Inspection Procedure 1: Communication Between the Scan Tool and WC-ECU Cannot Be Established

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.(Inspection Procedure 3: AWC-ECU Power Supply Circuit Malfunction)
NO: Repair the CAN bus lines.