Inspection Procedure 1: Scan Tool Communication Only With ABS/TCL/Skid Control System Is Impossible.

INSPECTION PROCEDURE 1: Scan tool communication only with ABS/TCL/Skid control system is impossible.

CAUTION
^ If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to Trouble code diagnosis Diagnosis).
^ Whenever ECU is replaced, ensure that the CAN bus lines are normal.
^ When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor, the G and yaw rate sensor and brake fluid pressure sensor.

COMMENTS ON TROUBLE SYMPTOM
When scan tool cannot communicate with the ABS/TCL/ASC system, the CAN bus line, ASC-ECU power supply circuit system, or ASC-ECU may be faulty.

PROBABLE CAUSES
^ Damaged wiring harness and connectors
^ ASC-ECU malfunction
^ Wrong routing of scan tool harness
^ Abnormality in battery or alternator
^ Abnormality in power supply voltage to ASC-ECU
^ ECU malfunction of other system

DIAGNOSIS

Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. M.U.T.-III CAN bus diagnostics
Use scan tool to diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Check the power supply circuit, and repair if necessary (Refer to Inspection Procedure 13: ASC-ECU Power Supply Circuit System).
NO: Repair the CAN bus lines (Refer to CAN Bus Diagnosis table Diagnosis).