Code No. P1571: Stop Lamp Switch System

OPERATION

Battery positive voltage is supplied to the stop lamp switch (terminal No. 2 and No. 4).
When the brake pedal is depressed, battery positive voltage is applied to the engine-ECU terminal No. 34 and No. 94.

DIAGNOSIS CODE SET CONDITIONS

Check Condition

The auto-cruise control indicator lamp illuminates.

Judgement Criteria

Open/short in stop lamp switch circuit.
Open circuit in the brake switch circuit (between engine-ECU terminal No. 94 and earth).

PROBABLE CAUSES

Damaged harness or connector.
Malfunction of the stop lamp switch.
Malfunction of the engine-ECU.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list.

Item 135: Stop lamp switch (Refer to data list reference table

Q. Is the check result normal?

	Go to Step 11.

	Go to Step 2.

STEP 2. Check the stop lamp operation.

Check the stop lamp operation.

OK:

Brake pedal depressed: Stop lamp will illuminate
Brake pedal not depressed: Stop lamp does not illuminate

Q. Is the check result normal?

	Go to Step 3.

	Go to Step 5.

STEP 3. Connectors check: D-213 engine-ECU connector and D-113 J/C (6).

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the damaged components. Then go to Step 19.

STEP 4. Check the harness between engine-ECU connector D-213 terminal No. 34 and stop lamp switch connector D-134 terminal No. 1.

Q. Is the check result normal?

	Go to Step 10.

	Repair the damaged harness wire. Then go to Step 19.

STEP 5. Measure the voltage at stop lamp switch connector D-134.

(1)Disconnect stop lamp switch connector D-134.

(2)Measure the voltage between stop lamp switch connector D-134 terminal No. 2 and earth.
OK: System voltage

(3)Connect stop lamp switch connector D-134.

Q. Is the check result normal?

	Go to Step 9.

	Go to Step 6.

STEP 6. Connector check: D-134 stop lamp switch connector.

Q. Is the check result normal?

	Go to Step 7.

	Repair or replace the damaged components. Then go to Step 19.

STEP 7. Check the harness between stop lamp switch connector D-134 terminal No. 2 and fuse No. 16 at the relay box in engine compartment.

Q. Is the check result normal?

	Go to Step 8.

	Repair the damaged harness wire. Then go to Step 19.

STEP 8. Check the fuse No. 16 at the relay box in engine compartment.

Q. Is the check result normal?

	Return to Step 1.

	Check the stop lamp system harness and replace the fuse. Then go to Step 19.

STEP 9. Check the stop lamp switch.

(1)Remove the stop lamp switch (Refer to GROUP 35A - Brake Pedal

(2)Connect an ohmmeter to the stop lamp switch between terminals No. 1 and No. 2.

(3)Check for continuity between the terminals when the plunger of the stop lamp switch is pushed in and when it is released.
OK: The stop lamp switch is operating properly if the circuit is open between terminals No. 1 and No. 2 when the plunger is pushed in to a depth of within approximately 4.0 mm from the outer case edge surface, and if the resistance value is less than 2 ohms between terminals No. 1 and No. 2 when it is released.

Q. Is the check result normal?

Install the stop lamp switch (Refer to GROUP 35A - Brake Pedal

). Then go to Step 10.

Replace the stop lamp switch (Refer to GROUP 35A - Brake Pedal

). Then go to Step 19.

STEP 10. M.U.T.-III data list.

Item 135: Stop lamp switch (Refer to data list reference table

Q. Is the check result normal?

	Go to Step 11.

	Replace the engine-ECU (Refer to GROUP 13D - Engine-ECU ). Then go to Step 19.

STEP 11. M.U.T.-III data list.

Item 134: Brake switch (Refer to data list reference table

Q. Is the check result normal?

	Go to Step 18.

	Go to Step 12.

STEP 12. Measure the voltage at engine-ECU connector D-215.

(1)Turn the ignition switch to the "ON" position.

(2)Measure the voltage between engine-ECU connector D-215 terminal No. 94 and earth.
OK:

Brake pedal depressed: System voltage
Brake pedal not depressed: 1 V or less

(3)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the check result normal?

	Go to Step 17.

	Go to Step 13.

STEP 13. Connectors check: D-134 stop lamp switch connector and D-215 engine-ECU connector.

Q. Is the check result normal?

	Go to Step 14.

	Repair or replace the damaged components. Then go to Step 19.

STEP 14. Check the harness between engine-ECU connector D-215 terminal No. 94 and stop lamp switch connector D-134 terminal No. 4.

Q. Is the check result normal?

	Go to Step 15.

	Repair the damaged harness wire. Then go to Step 19.

STEP 15. Check the harness between stop lamp switch connector D-134 terminal No. 3 and earth.

Q. Is the check result normal?

	Go to Step 16.

	Repair the damaged harness wire. Then go to Step 19.

STEP 16. Check the stop lamp switch.

(1)Remove the stop lamp switch (Refer to GROUP 35A - Brake Pedal

(2)Connect an ohmmeter to the stop lamp switch between terminals No. 3 and No. 4.

(3)Check for continuity between the terminals when the plunger of the stop lamp switch is pushed in and when it is released.
OK: The stop lamp switch is operating properly if the circuit is open between terminals No. 3 and No. 4 when the plunger is released, and if resistance value is less than 2 ohms between terminals No. 3 and No. 4 when the plunger is pushed in to a depth of within approximately 4.5 mm from the outer case edge surface.

Q. Is the check result normal?

Install the stop lamp switch (Refer to GROUP 35A - Brake Pedal

). Then go to Step 17.

Replace the stop lamp switch (Refer to GROUP 35A - Brake Pedal

). Then go to Step 19.

STEP 17. M.U.T.-III data list.

Item 134: Brake switch (Refer to data list reference table

Q. Is the check result normal?

	It can be assumed that this malfunction is intermittent (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunction ).

	Replace the engine-ECU (Refer to GROUP 13D - Engine-ECU ). Then go to Step 19.

STEP 18. Read the diagnosis code.

(1)Disconnect the negative (-) battery terminal, and erase the diagnosis code of the auto-cruise control system.

(2)Connect the negative (-) battery terminal.

(3)Turn the ignition switch to the "ON" position, and press the "ON/OFF" (MAIN) switch to turn the auto-cruise control system to ON.

(4)With the auto-cruise control switches not operated, depress the brake pedal for several seconds, and then read the diagnosis code of the auto-cruise control system.

Q. Is diagnosis code No. P1571 set?

	Replace the engine-ECU (Refer to GROUP 13D - Engine-ECU ). Then go to Step 19.

	It can be assumed that this malfunction is intermittent (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunction ).

STEP 19. Read the diagnosis code.

(1)Disconnect the negative (-) battery terminal, and erase the diagnosis code of the auto-cruise control system.

(2)Connect the negative (-) battery terminal.

(3)Turn the ignition switch to the "ON" position, and press the "ON/OFF" (MAIN) switch to turn the auto-cruise control system to ON.

(4)With the auto-cruise control switches not operated, depress the brake pedal for several seconds, and then read the diagnosis code of the auto-cruise control system.

Q. Is diagnosis code No. P1571 set?

	Return to Step 1.

	The procedure is complete.