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Home >> Mitsubishi >> 2010 >> Lancer Evolution SE >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Continuously Variable Transaxle On-Vehicle Service -- Lancer) >> Diagnosis >> Diagnostic Trouble Code Procedures >> DTC P0703: Malfunction of Stoplight Switch >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different variant/trim than selected.
  1. 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? 

    1. YES:  Go to Step 2.
    2. NO:  Repair the CAN bus lines (Refer to DIAGNOSIS CODE CHART ).
  2. 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? 

    1. YES:  Intermittent malfunction
    2. NO:  Go to Step 3.
  3. STEP 3. Check the following connector: 
    • C-304 ETACS-ECU connector
    • C-312 ETACS-ECU connector
    • C-32 Stoplight switch connector

      Check the contact status of the terminals.

      Q: Is the check result normal? 

      1. YES:  Go to Step 4.
      2. NO:  Repair the defective connector.
  4. STEP 4. Stoplight Switch Check 

    Refer to BRAKE PEDAL .

    Q: Is the check result normal? 

    1. YES:  Go to Step 5.
    2. NO:  Replace the stoplight switch.
  5. STEP 5. Check for open circuit in the wiring harness between the stoplight switch connector and the ETACS-ECU connector. 

    Between C-32 Stoplight switch connector (terminal No. 2) and C-304 ETACS-ECU harness-side connector (terminal No. 1)

    Q: Is the check result normal? 

    1. YES:  Go to Step 6.
    2. NO:  Repair the wiring harness.
  6. STEP 6. Check for open circuit or short to ground 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-38 joint connector (4) (terminal No. 10)

    Q: Is the check result normal? 

    1. YES:  Go to Step 7.
    2. NO:  Repair the wiring harness.
  7. STEP 7. Check for open circuit in wiring harness between the stoplight switch connector and the joint connector (4) 

    Between C-32 stoplight switch connector (terminal No. 1) and C-38 joint connector (4) (terminal No. 10)

    Q: Is the check result normal? 

    1. YES:  Go to Step 8.
    2. NO:  Repair the wiring harness.
  8. STEP 8. Symptom recheck after erasing diagnosis code 

    Q: Is the check result normal? 

    1. YES:  Intermittent malfunction
    2. NO:  Replace the ETACS-ECU, and then go to Step 9.
  9. STEP 9. Symptom recheck after erasing diagnosis code 

    Q: Is the check result normal? 

    1. YES:  Intermittent malfunction
    2. NO:  Replace TCM.
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