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Home >> Mitsubishi >> 2005 >> Eclipse GS, Standard >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Auto-Cruise Control >> Diagnostic Trouble Code Procedures >> DTC 14: Stoplight Switch System >> Diagnosis

DTC 14: Stoplight Switch System: Diagnosis

Required Special Tool: 

  1. STEP 1. Check the output circuit voltage at stoplight switch connector C-03 (terminal number 3) by backprobing. 
    1. Do not disconnect stoplight switch connector C-03.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 3 and ground by backprobing.
      Fig 1: Measuring Voltage Between Terminal 3 And Ground
      G02424841Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the voltage approximately battery positive voltage? 

    1. YES  : Go to  Step 3.
    2. NO  : Go to Step 2.
  2. STEP 2. Check stoplight switch connector C-03. 
    Fig 2: Identifying Stoplight Switch Connector C-03
    G02424842Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the connector damaged? 

    1. YES  : Repair or replace connector. Refer to HARNESS CONNECTOR INSPECTION . Then check that diagnostic trouble code 14 is not output.
    2. NO  : Go to  Step 13.
  3. STEP 3. Check the output circuit voltage at stoplight switch connector C-03 (terminal number 4) by backprobing. 
    1. Do not disconnect stoplight switch connector C-03.
    2. Turn the ignition switch to the "ON" position and the auto-cruise control main switch to the "ON" position.
    3. Measure the voltage between terminal 4 and ground by backprobing.
      Fig 3: Measuring Voltage Between Terminal 4 And Ground
      G02424843Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the voltage approximately battery positive voltage? 

    1. YES  : Go to  Step 6.
    2. NO  : Go to Step 4.
  4. STEP 4. Check stoplight switch connector C-03. 
    Fig 4: Identifying Stoplight Switch Connector C-03
    G02424844Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the connector damaged? 

    1. YES  : Repair or replace connector. Refer to HARNESS CONNECTOR INSPECTION . Then check that diagnostic trouble code 14 is not output.
    2. NO  : Go to Step 5.
  5. STEP 5. Check the stoplight switch. 
    1. Disconnect stoplight switch connector C-03.
    2. Connect an ohmmeter to the stoplight switch between terminals 3 and 4, and check whether there is continuity when the plunger of the stoplight switch is pushed in and an open circuit when it is released.
      Fig 5: Connecting Ohmmeter To Stoplight Switch Between Terminals 3 And 4
      G02424845Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    3. The stoplight switch is in good condition if the circuit is open when the plunger is pushed in to a depth of within 4 mm (0.2 inch) from the outer case edge surface, and if there is continuity when it is released.
      Fig 6: Checking Continuity
      G02424846Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the circuit is open? 

    1. YES  : Replace the stoplight switch. Refer to , BRAKE PEDAL . Then check that a diagnostic trouble code 14 is not output.
    2. NO  : Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU (Refer to AUTO-CRUISE CONTROL  .). Then check that diagnostic trouble code 14 is not output.
  6. STEP 6. Check the output circuit voltage at auto-cruise control vacuum pump connector A-01 (terminal number 1) by backprobing. 
    1. Do not disconnect auto-cruise control vacuum pump connector A-01.
    2. Turn the ignition switch to the "ON" position and the auto-cruise control main switch to the "ON" position.
    3. Measure the voltage between terminal 1 and ground by backprobing.
      Fig 7: Measuring Voltage Between Terminal 1 And Ground
      G02424847Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the voltage approximately battery positive voltage? 

    1. YES  : Go to  Step 8.
    2. NO  : Go to Step 7.
  7. STEP 7. Check auto-cruise control vacuum pump connector A-01 and intermediate connector C-06. 
    Fig 8: Identifying Auto-Cruise Control Vacuum Pump Connector A-01
    G02424848Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 9: Identifying Intermediate Connector C-06
    G02424849Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is any connector damaged? 

    1. YES  : Repair or replace connector. Refer to HARNESS CONNECTOR INSPECTION . Then check that diagnostic trouble code 14 is not output.
    2. NO  : Check the harness wire between stoplight switch connector C-03 and auto-cruise control vacuum pump connector A-01 for open circuit or damage. Then repair if necessary. Then check that diagnostic trouble code 14 is not output.
  8. STEP 8. Check the output circuit voltage at auto-cruise control-ECU connector C-20 (terminal numbers 7,8 and 16) by backprobing. 
    1. Do not disconnect auto-cruise control-ECU connector C-20.
    2. Turn the ignition switch to the "ON" position and the auto-cruise control main switch to the "ON" position.
    3. Measure the voltage between terminal 7 and ground by backprobing.
      • Voltage should be battery positive voltage. [When decelerating with the "SET" switch while driving at constant speed (Release valve open).]
        • Fig 10: Measuring Voltage Between Terminal 7, 8 Or 16 And Ground By Backprobing
        G02424850Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Measure the voltage between terminal 8 and ground by backprobing.
      • Voltage should be battery positive voltage. [When decelerating with the "SET" switch while driving at constant speed. (Control valve open).]
    5. Measure the voltage between terminal 16 and ground by backprobing.
      • Voltage should be battery positive voltage. (When the motor is stopped during a constant road speed.)
    6. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Are all of the above values satisfied? 

    1. YES  : Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU (Refer to AUTO-CRUISE CONTROL  .). Then check that diagnostic trouble code 14 is not.
    2. NO  : Go to Step 9.
  9. STEP 9. Check auto-cruise control-ECU connector C-20 and intermediate connector C-94. 
    Fig 11: Identifying Auto-Cruise Control-ECU Connector C-20
    G02424851Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 12: Identifying Intermediate Connector C-94
    G02424852Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the connector damaged? 

    1. YES  : Repair or replace connector. Refer to HARNESS CONNECTOR INSPECTION . Then check that diagnostic trouble code 14 is not output.
    2. NO  : Go to Step 10.
  10. STEP 10. Check auto-cruise control vacuum pump connector A-01. 
    Fig 13: Identifying Auto-Cruise Control Vacuum Pump Connector A-01
    G02424853Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the connector damaged? 

    1. YES  : Repair or replace connector. Refer to HARNESS CONNECTOR INSPECTION . Then check that diagnostic trouble code 14 is not output.
    2. NO  : Go to Step 11.
  11. STEP 11. Check the auto-cruise vacuum pump. 
    Fig 14: Checking Auto-Cruise Vacuum Pump
    G02424854Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    1. Disconnect the vacuum hose from the auto-cruise vacuum pump and connect a vacuum gauge to the vacuum pump.
    2. Disconnect the vacuum pump connector.
    3. Check the auto-cruise vacuum pump and valves according to the following procedure:
      • Connect the positive battery terminal to auto-cruise vacuum pump connector terminal 1, and the negative battery terminal to terminals 2, 3, and 4. The vacuum gauge should read 27 kPa (8.0 in Hg) or more.
      • The vacuum should be maintained when terminal 4 is disconnected from the negative battery terminal while terminals 1, 2, and 3 remain connected. Then the vacuum gauge should read 0 kPa (0 in Hg) when terminal 2 is disconnected from the negative battery terminal while terminals 1, and 3 remain connected.
      • The vacuum should be maintained when terminal 4 is disconnected from the negative battery terminal while terminals 1, 2, and 3 remain connected. Then the vacuum gauge should read 0 kPa (0 in Hg) when terminal 3 is disconnected from the negative battery terminal while terminals 1, and 2 remain connected.

    Q: Are all of the above values satisfied? 

    1. YES  : Go to Step 12.
    2. NO  : Replace the auto-cruise vacuum pump (Refer to AUTO-CRUISE CONTROL  .). Then check that diagnostic trouble code 14 is not output.
  12. STEP 12. Check the harness wire between auto-cruise control vacuum pump connector A-01 (terminal numbers 2,3 and 4) and auto-cruise control-ECU connector C-20 (terminal numbers 7,8 and 16). 
    Fig 15: Identifying Harness Wire Connector A-01
    G02424855Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 16: Identifying Auto-Cruise Control-ECU Connector C-20
    G02424856Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is any harness wire between auto-cruise control vacuum pump connector A-01 (terminal numbers 2,3 and 4) and auto-cruise control-ECU connector C-20 (terminal numbers 7,8 and 16) damaged? 

    1. YES  : Repair harness wire and then check that diagnostic trouble code 14 is not output.
    2. NO  : Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU (Refer to AUTO-CRUISE CONTROL  .). Then check that diagnostic trouble code 14 is not output.
  13. STEP 13. Check the output circuit voltage at auto-cruise control-ECU connector C-20 (terminal number 5) by backprobing. 
    1. Do not disconnect auto-cruise control-ECU connector C-20.
    2. Turn the ignition switch to the "ON" position and the auto-cruise control main switch to the "ON" position.
    3. Measure the voltage between terminal 5 and ground by backprobing.
      Fig 17: Measuring Voltage Between Terminal 5 And Ground
      G02424857Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the voltage approximately battery positive voltage? 

    1. YES  : Go to Step 14.
    2. NO  : Go to  Step 15.
  14. STEP 14. Check intermediate connector C-89. 
    Fig 18: Identifying Intermediate Connector C-89
    G02424858Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the connector damaged? 

    1. YES  : Repair or replace connector. Refer to HARNESS CONNECTOR INSPECTION . Then check that diagnostic trouble code 14 is not output.
    2. NO  : Check the harness wire between auto-cruise control-ECU connector C-20 and stoplight switch connector C-03 for open circuit or damage. Then repair if necessary. Then check that diagnostic trouble code 14 is not output.
  15. STEP 15. Check auto-cruise control-ECU connector C-20. 
    Fig 19: Identifying Auto-Cruise Control-ECU Connector C-20
    G02424859Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the connector damaged? 

    1. YES  : Repair or replace connector. Refer to HARNESS CONNECTOR INSPECTION . Then check that diagnostic trouble code 14 is not output.
    2. NO  : Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU (Refer to AUTO-CRUISE CONTROL  .). Then check that diagnostic trouble code 14 is not output.
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