Inspection Procedure 26: Stop lamp switch system








OPERATION



  • The battery voltage is applied to the stop lamp switch (terminal No. 2).
  • The stop lamp switch output terminal (terminal No. 1) inputs the switch signal to the engine-A/T-ECU (terminal No. 39).

FUNCTION



  • The system checks whether the vehicle has the illuminating stop lamp or not, and inputs the signal to the engine-A/T-ECU. The engine-A/T-ECU knows the vehicle state through the stop lamp switch signal and carries out control of the each system.

PROBABLE CAUSES



  • Failed stop lamp switch
  • Open/short circuit in stop lamp switch or loose connector contact
  • Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check for height of brake pedal.

  • Check for height of brake pedal (Refer to GROUP 35A - On-vehicle Service - Brake Pedal Check And Adjustment ).

Q. Is the check result normal?
Go to Step 2 .
Adjust.

STEP 2. Connector check: D-134 stop lamp switch connector

Q. Is the check result normal?
Go to Step 3 .
Repair or replace the connector.

STEP 3. Check the stop lamp switch.

  • Check the stop lamp switch (Refer to GROUP 35A - Brake Pedal Inspection ).

Q. Is the check result normal?
Go to Step 4 .
Replace the stop lamp switch.

STEP 4. Perform voltage measurement at D-134 stop lamp switch connector

  • Disconnect the connector, and measure it at harness side.
  • Voltage between terminal No. 2 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 5 .

    Check for the intermediate connector D-241, and repair if necessary. If intermediate connector is normal, check and repair harness between D-134 (terminal No. 2) stop lamp switch connector and battery.

    • Check power supply line open/short circuit supply.

STEP 5. Connector check: D-214 engine-A/T-ECU connector


Q. Is the check result normal?
Go to Step 6 .
Repair or replace the connector.

STEP 6. Perform voltage measurement at D-214 engine-A/T-ECU connector.

  • Disconnect connector, and measure at the harness side.
  • Ignition switch: ST
  • Voltage between terminal No. 39 and the earth.
OK:
    System voltage (Brake pedal: Depressed)
    1 V or less (Brake pedal: Released)

Q. Is the check result normal?
Go to Step 8 .
Go to Step 7 .

STEP 7. Check harness between D-134 (terminal No. 1) stop lamp switch connector and D-214 (terminal No. 39) engine-A/T-ECU connector.


note Before checking harness, check intermediate connector D-230 and repair if necessary.

  • Check output line open/short circuit and damage.

Q. Is the check result normal?
For a short circuit, check and repair harness and the connector for the stop lamp switch output signal.
Repair the damaged harness wire.

STEP 8. M.U.T.-III data list

  • Refer to Data List Reference Table .

  1. Item 74: Stop lamp switch

Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
Replace the engine-A/T-ECU.