Inspection Procedure 13: The stop lamp switch signal is not received.


caution Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM




  • ABS, ASC
  • Shift lock mechanism
  • OSS

PROBABLE CAUSES



  • Malfunction of stop lamp switch
  • Malfunction of stop lamp relay*
  • Malfunction of ETACS-ECU
  • Damaged harness wires and connectors
note *: The stop lamp relay cannot be inspected because it is a semiconductor relay.

DIAGNOSIS PROCEDURE


STEP 1. Connector check: C-25 stop lamp switch connector, C-29 stop lamp relay connector, C-403, C-410 ETACS-ECU connector


Q. Is the check result normal?





STEP 2. Resistance measurement at the C-29 stop lamp relay connector


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between stop lamp relay connector terminal No. 5 and the body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?





STEP 3. Wiring harness check between the C-29 stop lamp relay connector terminal No. 5 and the body earth.



  • Check the earth wires for open circuit.

Q. Is the check result normal?





STEP 4. Check the stop lamp switch.



Q. Is the check result normal?





STEP 5. Voltage measurement at the C-29 stop lamp relay connector


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the voltage between stop lamp relay connector terminal No. 4 and the body earth.
OK: System voltage
(3)Stop lamp switch: ON
(4)Measure the voltage between stop lamp relay connector terminal No. 7 and the body earth.
OK: System voltage

Q. Is the check result normal?





STEP 6. Check the following wiring harness.




  • Wiring harness from C-403 ETACS-ECU connector terminal No. 1 to C-25 stop lamp switch connector terminal No. 1.
  • Wiring harness from C-25 stop lamp switch connector terminal No. 1 to C-29 stop lamp relay connector terminal No. 6.
  • Wiring harness from C-25 stop lamp switch connector terminal No. 2 to C-29 stop lamp relay connector terminal No. 7.

Q. Is the check result normal?





STEP 7. Measure the voltage at the C-410 ETACS-ECU connector


(1)Measure by backprobing without disconnecting the ETACS-ECU connector and stop lamp switch connector.
(2)Disconnecting the C-29 stop lamp relay connector.
(3)Measure the voltage between the ETACS-ECU connector terminal No.16 and the body earth.
OK:
    When the brake pedal is released: Approximately 0 V - 5 V (pulse)
    When the brake pedal is depressed: Approximately system voltage

Q. Is the check result normal?





STEP 8. Check the wiring harness between C-410 ETACS-ECU connector terminal No.16 and C-29 stop lamp relay connector terminal No.7



  • Check the signal line for open circuit.

Q. Is the check result normal?





STEP 9. M.U.T.-III data list



Item No.
 Item name
 Normal condition
Item 290
 Stop lamp switch
 ON
OK: Normal condition is displayed.

Q. Is the check result normal?