Inspection Procedure 28: 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-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 39).

FUNCTION

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

POSSIBLE CAUSES

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

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-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> connector

Q. Is the check result normal?

	Go to Step 6 .

	Repair or replace the connector.

STEP 6. Perform voltage measurement at D-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> 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-244 (terminal No. 39) engine-ECU <M/T> connector or D-214 (terminal No. 39) engine-A/T-ECU <A/T> 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 .

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-ECU <M/T> or engine-A/T-ECU <A/T>.