Super All Wheel Control

DTC C1000: Stoplight Switch System





CAUTION:
^ If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
^ Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION
AWC-ECU receives signals of stoplight switch from ETACS-ECU via the CAN bus lines.
^ The vehicle has run for a long time with the stop light switch turned ON.
^ With the stoplight switch OFF, the vehicle speed is decelerated suddenly.

PROBABLE CAUSES
^ Incorrect adjustment of stoplight switch position
^ Malfunction of stoplight switch
^ Stoplight malfunction
^ Damaged harness wires and connectors
^ Malfunction of the ETACS-ECU
^ Malfunction of AWC-ECU

DTC SET CONDITIONS
This diagnostic trouble code is set when the abnormality below is detected:

DIAGNOSTIC PROCEDURE

STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.

Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 2.

STEP 2. Check whether the DTC is reset.

Q: Is DTC No. C1000 set?
YES: Go to Step 3.
NO: This diagnosis is complete.

STEP 3. Check of the stoplight on and off
Check that the stoplight illuminates when the brake pedal is depressed, and the stoplight goes out when the brake pedal is released.

Q: Is the check result normal?
YES: Go to Step 16.
NO: Go to Step 4.

STEP 4. Stop light switch installation status check

Q: Is the check result normal?
YES: Go to Step 5.
NO: Install the stop light switch correctly. Then go to Step 21.

STEP 5. Check the stop light switch.

Q: Is the check result normal?
YES: Go to Step 6.
NO: Replace the stoplight switch. Then go to Step 21.

STEP 6. ETACS-ECU connector check: C-304

Q: Is the check result normal?
YES: Go to Step 7.
NO: Repair the defective connector. Then go to Step 21.

STEP 7. Measure the voltage at the C-304 ETACS-ECU connector.
With C-304 ETACS-ECU connector connected, measure the voltage between the terminal No. 1 and the body ground.
OK: Battery voltage (when the brake pedal is released)

Q: Is the check result normal?
YES: Go to Step 10.
NO: Go to Step 8.

STEP 8. ETACS-ECU fuse No. 2 check

Q: Is the check result normal?
YES: Replace the ETACS-ECU. Then go to Step 21.
NO: Replace fuse No. 2. Then go to Step 9.

STEP 9. Check the wiring harness between C-304 ETACS-ECU connector terminal No. 1 and C-48 stoplight switch connector terminal No. 2.
Check that the wiring harness is not shorted (short to ground).

Q: Is the check result normal?
YES: Go to Step 21.
NO: Repair the wiring harness. Then go to Step 21.

STEP 10. Stop light switch connector check: C-48

Q: Is the check result normal?
YES: Go to Step 11.
NO: Repair the defective connector. Then go to Step 21.

STEP 11. Voltage measurement at the C-48 stoplight switch connector
Disconnect the connector, and measure the voltage between terminal No. 2 and ground at the wiring harness side.
OK: Battery positive voltage

Q: Is the check result normal?
YES: Go to Step 13.
NO: Go to Step 12.

STEP 12. Check the wiring harness between C-304 ETACS-ECU connector terminal No. 1 and C-48 stoplight switch connector terminal No. 2.
Check the wiring harness for open circuit.

Q: Is the check result normal?
YES: Go to Step 13.
NO: Repair the wiring harness. Then go to Step 21.

STEP 13. J/C (4), intermediate connector check: C-43, C-47

Q: Is the check result normal?
YES: Go to Step 14.
NO: Repair the defective connector. Then go to Step 21.

STEP 14. Voltage measurement at C-43 J/C (4)
Disconnect the connector, and measure the voltage between terminal No. 2 and ground at the wiring harness side.
OK: Battery positive voltage (brake pedal depressed)

Q: Is the check result normal?
YES: Go to Step 16.
NO: Go to Step 15.

STEP 15. Check the wiring harness between C-48 stoplight switch connector terminal No. 1 and the C-43 J/C (4) terminal No. 2.
Check the wiring harness for open or short circuit (short to ground).

Q: Is the check result normal?
YES: Go to Step 16.
NO: Repair the wiring harness. Then go to Step 21.

STEP 16. ETACS-ECU connector check: C-312

Q: Is the check result normal?
YES: Go to Step 17.
NO: Repair the defective connector. Then go to Step 21.

STEP 17. Measure the voltage at the C-312 ETACS-ECU connector.
Measure the voltage between C-312 ETACS-ECU connector terminal No. 16 and the body ground.
^ OK: 1 V or less (brake pedal released)
^ OK: Battery positive voltage (brake pedal depressed)

Q: Is the check result normal?
YES: Go to Step 19.
NO: Go to Step 18.

STEP 18. Check the wiring harness between C-312 ETACS-ECU connector terminal No. 16 and C-48 stoplight switch connector terminal No. 1.
Check the wiring harness for open circuit.

Q: Is the check result normal?
YES: Go to Step 19.
NO: Repair the wiring harness. Then go to Step 21.

STEP 19. Scan tool service data
Item No. 39: Stoplight switch.

Q: Is the check result normal?
YES: Go to Step 20.
NO: Replace the ETACS-ECU. Then go to Step 21.

STEP 20. Check whether the DTC is reset.

Q: Is DTC No. C1000 set?
YES: Replace the AWC-ECU. Then go to Step 21.
NO: Intermittent malfunction.

STEP 21. Check whether the DTC is reset.

Q: Is DTC No. C1000 set?
YES: Return to Step 1.
NO: This diagnosis is complete.