Inspection Procedure 1

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 diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines CAN Bus Line Diagnostics Flow ).
- 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 (Refer to Testing and Inspection , Testing and Inspection and Testing and Inspection ).

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 generator
- Abnormality in power supply voltage to ASC-ECU
- ECU malfunction of other system

DIAGNOSIS

STEP 1. Using scan tool MB991958, diagnose the CAN bus line

Use scan tool MB991958 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 12).
NO Repair the CAN bus lines CAN Bus Diagnostics Chart).