Code No. P0703: Malfunction of Stop Lamp Switch










DIAGNOSTIC FUNCTION


CVT-ECU detects malfunction using the stop lamp switch signal sent from the ETACS-ECU.

JUDGMENT CRITERIA


Drive the vehicle at 30 km/h or more for 10 seconds, and then turn the ignition switch to the OFF position. In this sequential operation, no variation has been found in the stop lamp switch input signal in two consecutive times.

PROBABLE CAUSES



DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use M.U.T.-III to perform the CAN bus diagnosis.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C, Troubleshooting - Diagnosis Code Chart ).

STEP 2. M.U.T.-III data list
Item 50: Brake switch
OK: The service data changes in response to the brake operation.

Q. Is the check result normal?
Intermittent malfunction
Go to Step 3.

STEP 3. Check the following connector:

  • C-304 ETACS-ECU connector
  • C-309 ETACS-ECU connector
  • C-312 ETACS-ECU connector
  • C-24 Stoplamp switch connector
Check the contact status of the terminals.

Q. Is the check result normal?
Go to Step 4.
Repair the defective connector.

STEP 4. Stoplamp Switch Check
Refer to GROUP 35A, Brake Pedal .

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

STEP 5. Check for open circuit in the wiring harness between the stoplamp switch connector and the ETACS-ECU connector.
Between C-24 Stoplamp switch connector (terminal No.2) and C-304 ETACS-ECU harness-side connector (terminal No.1)

Q. Is the check result normal?
Go to Step 6.
Repair the wiring harness.

STEP 6. Check for open circuit or short to earth in wiring harness between the ETACS-ECU connector and the joint connector (4)
Between C-312 ETACS-ECU harness-side connector (terminal No.16) and C-30 joint connector (4) (terminal No.10)

Q. Is the check result normal?
Go to Step 7.
Repair the wiring harness.

STEP 7. Symptom recheck after erasing diagnosis code

Q. Is the check result normal?
Intermittent malfunction
Replace the ETACS-ECU, and then go to Step 8.

STEP 8. Symptom recheck after erasing diagnosis code

Q. Is the check result normal?
Intermittent malfunction
Replace CVT-ECU.