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 - Troubleshooting/Diagnosis function <4B1>, GROUP 13B - Troubleshooting/Diagnosis function <6B3> or Refer to 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).

Q. Is the check result normal?

	Replace the hydraulic unit (integrated with ASC-ECU). 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.