Inspection Procedure 1: When the Ignition Switch is Turned to the "ON" position (Engine Stopped), the brake warning lamp does not Illuminate.












OPERATION

  • The brake warning lamp illuminates or goes out by the transistor control inside the ASTC-ECU. In this circuit, when the transistor is ON, the brake warning lamp goes out. Even when the ASTC-ECU connector is connected improperly or the ASTC-ECU is disabled, the brake warning lamp illuminates by the circuit in the meter.
  • Other than the case when the system has failed, the ASTC-ECU illuminates the brake warning lamp for approximately 3 seconds during the initial check with the ignition switch being in the ON position.
  • The brake warning lamp illuminates also in the cases when the parking brake is operated, and when the brake fluid level is the specified value or less.

COMMENT ON TROUBLE SYMPTOM
Possible causes include the combination meter power circuit, disconnected earth circuit, dead lamp bulb, or short circuited brake warning lamp.

PROBABLE CAUSES
The most likely causes for this case are:

  • Blown fuse
  • Damaged wiring harness or connector
  • Burnt out brake warning lamp bulb
  • Combination meter defect
  • Malfunction of the ASTC-ECU

DIAGNOSIS

STEP 1. Voltage measurement at combination meter connector D-02.
(1)Do not disconnect combination meter connector D-02, and check at the harness side.
(2)Turn the ignition switch to the "ON" position.
(3)Measure the voltage between terminal 45 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 2.
Replace the combination meter. Then go to Step 5.

STEP 2. Connector check: D-02 combination meter connector, D-223 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 5.

STEP 3. Check the harness wire between the combination meter connector D-02 terminal 45 and ASTC-ECU connector D-223 terminal 81.

Q. Is the check result normal?
Go to Step 4.
Repair the harness wire. Then go to Step 5.

STEP 4. Retest the system.

Q. Does the brake warning lamp illuminate for 3 seconds when the ignition switch is turned to the "ON" position with engine stopped or upon start-up?
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the ASTC-ECU. Then go to Step 5.

STEP 5. Retest the system.

Q. Does the brake warning lamp illuminate for 3 seconds when the ignition switch is turned to the "ON" position with engine stopped or upon start-up?
The procedure is complete.
Start over at Step 1.