Inspection Procedure 11: ASC does not operate or faulty ASC operate.


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 GROUP 54C - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.

COMMENTS ON TROUBLE SYMPTOM
In case of this trouble symptom, the stability control/TCL system operation may be disabled. Diagnosis code may be set by the stability control/TCL system using M.U.T.-III.

PROBABLE CAUSES

  • Low battery output
  • Wiring harness or connector failure of CAN bus line
  • ASC-ECU malfunction
  • Engine coding data problem

DIAGNOSIS PROCEDURE

STEP 1. Diagnosis code check
Use M.U.T.-III to check the diagnosis code for the ASC system (Refer to ).

Q. Is the check result normal?
Go to Step 2
Carry out the diagnosis for the diagnosis code (Refer to ).

STEP 2. Engine ECU coding data check
Using M.U.T.-III, check if any abnormality is present to the coding data below which are stored in the engine-ECU (Refer to GROUP 00 - Precautions before Service/Coding List ).
A.S.C.
    OK: Available

Q. Is the check result normal?
Go to Step 4
Go to Step 3

STEP 3. Engine ECU coding data check
Perform the variant coding to the Engine ECU.

Q. Is the check result normal?
Go to Step 5
Replace the engine ECU (Refer to GROUP 13A - Engine-ECU <4B1>, GROUP 13C - Engine-ECU <4J1>, GROUP 13D - Engine-ECU <4N1>). Then go to Step 5.

STEP 4. Hydraulic unit (integrated with ASC-ECU) check
Check that the brake tube is correctly mounted to the hydraulic unit (integrated with ASC-ECU) (Refer to ).

Q. Is the check result normal?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 5.
Connect the brake tubes correctly, and repair or replace the external brake lines of the hydraulic unit (integrated with ASC-ECU).

STEP 5. Operation check

Q. Does stability control/TCL operate normally?
This diagnosis is complete.
Check the brake system related components other than the stability control/TCL system.