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 (Refer to GROUP 54C - CAN Bus Line Diagnostic 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 , and ).
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.
Is the check result normal?
Check the power supply circuit, and repair if necessary (Refer to ).
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
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Check the power supply circuit, and repair if necessary (Refer to 
).
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table