Inspection Procedure 9: After start-up of the engine, the ASC OFF switch cannot be operated. (ASC is fixed in the OFF position or cannot be turned OFF.)












OPERATION

  • When the ignition switch is ON, the active stability control system can be turned OFF by pressing the ASC OFF switch while the vehicle is stopped. (The switch cannot be operated if the vehicle speed exceeds 40 km/h.)
  • Even when the active stability control system is being OFF, it is automatically turned to ON if the vehicle speed exceeds 80 km/h.

COMMENT ON TROUBLE SYMPTOM
ASTC-ECU failure or the ASC OFF switch circuit failure is suspected.

PROBABLE CAUSES
The most likely causes for this case are:

  • Damaged wiring harness or connector
  • Malfunction of the ASC OFF switch
  • Malfunction of the ASTC-ECU

DIAGNOSIS

STEP 1. Check the ASC OFF switch
Refer to .

Q. Is the check result normal?
Go to Step 2.
Replace the ASC OFF switch. Then go to Step 7.

STEP 2. Connector check: D-203 ASC OFF switch connector, D-233 ASTC-ECU connector and D-230 intermediate connector.

Q. Is the check result normal?
Go to Step 3.
Repair the defective connector. Then go to Step 7.

STEP 3. Voltage measurement at ASTC-ECU connector D-233.
(1)Do not disconnect ASTC-ECU connector D-233, and check at the harness side by back probing.
(2)Turn the ignition switch to the "ON" position.
(3)Measure the voltage between terminal 13 and earth.
OK
    <When the ASC OFF switch is pressed>: Approximately 5 V
    <When the ASC OFF switch is not pressed>: 0 V

Q. Is the check result normal?
Replace the ASTC-ECU. Then go to Step 7.
Go to Step 4.

STEP 4. Check the harness wire between the ASC OFF switch connector D-203 terminal 2 and ASTC-ECU connector D-233 terminal 13.

Q. Is the check result normal?
Go to Step 5.
Repair the harness wire. Then go to Step 7.

STEP 5. Check the harness wire between the ASC OFF switch connector D-203 terminal 1 and ASTC-ECU connector D-233 terminal 17.

Q. Is the check result normal?
Go to Step 6.
Repair the harness wire. Then go to Step 7.

STEP 6. Retest the system.

Q. Can you operate the ASC OFF switch normally?
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Repair the ASTC-ECU. Then go to Step 7.

STEP 7. Retest the system.

Q. Can you operate the ASC OFF switch normally?
The procedure is complete.
Start over at Step 1.