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Home >> Mitsubishi >> 2003 >> Montero XLS >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Diagnostic Trouble Code Procedures >> Diagnostic Trouble Code Procedures <Automatic Transmission> >> DTC 15: Transmission Fluid Temperature Sensor System (Open Circuit) >> Diagnosis
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DTC 15: Transmission Fluid Temperature Sensor System (Open Circuit): Diagnosis

Required Special Tool: 

  1. STEP 1. Using scan tool MB991502, check data list item 15: Transmission Fluid Temperature Sensor. 
    CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
    1. Connect scan tool MB991502 to the data link connector.
      Fig 1: Connecting Scan Tool MB991502 To Data Link Connector
      G01850322Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Start the engine.
    3. Set scan tool MB991502 to data reading mode for item 15, Transmission Fluid Temperature Sensor.
      • When the engine is cool: Almost equal to the ambient temperature (atmospheric temperature)
        NOTE: Set scan tool MB991502 to data reading mode for item number 13, Intake Air Temperature (IAT) Sensor and note the temperature measurement. When the engine is cool, the temperature should be almost equal to the ambient temperature (atmospheric temperature), and the IAT sensor measurement should be approximately the same as the transmission fluid temperature sensor.
      • When the engine is warm: 70 to 80°C (158 to 176°F)
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the sensor operating properly? 

    1. YES :  It can be assumed that this malfunction is intermittent. Refer to HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS - How to Cope with Intermittent Malfunction.
    2. NO :  Go to Step 2.
  2. STEP 2. Measure the sensor output voltage at the A/T control solenoid valve assembly connector C-03 by backprobing. 
    1. Do not disconnect connector C-03.
      Fig 2: Locating A/T Control Solenoid Valve Assembly Connector C-03
      G01850323Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 1 and ground by backprobing.
      • When transmission fluid temperature is 20°C (68°F), voltage should measure between 3.8 and 4.0 volts.
      • When transmission fluid temperature is 40°C (104°F), voltage should measure between 3.2 and 3.4 volts.
      • When transmission fluid temperature is 80°C (176°F), voltage should measure between 1.7 and 1.9 volts.
      Fig 3: Measuring Voltage Between Terminal 1 And Ground By Backprobing
      G01850324Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage within the specified range? 

    1. YES :  Go to Step  6 .
    2. NO :  Go to Step 3.
  3. STEP 3. Measure the ground voltage at the A/T control solenoid valve assembly connector C-03 by backprobing. 
    1. Do not disconnect connector C-03.
      Fig 4: Locating A/T Control Solenoid Valve Assembly Connector C-03 For Ground Voltage
      G01850325Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 2 and ground by backprobing.
      • The voltage should measure 0.5 volt or less.
      Fig 5: Measuring Voltage Between Terminal 2 And Ground By Backprobing
      G01850326Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage 0.5 volt or less? 

    1. YES :  Go to Step 4.
    2. NO :  Go to Step  7 .
  4. STEP 4. Check the sensor output voltage at A/T control solenoid valve assembly connector C-03. 
    1. Disconnect connector C-03 and measure at the harness side.
      Fig 6: Locating Sensor Output Voltage At A/T Control Solenoid Valve Assembly Connector C-03
      G01850327Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 1 and ground.
      • The voltage should measure between 4.5 and 4.9 volts.
      Fig 7: Measuring Voltage Between Terminal 1 And Ground
      G01850328Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage between 4.5 and 4.9 volts? 

    1. YES :  Go to Step 5.
    2. NO :  Go to Step  9 .
  5. STEP 5. Check the transmission fluid temperature sensor at A/T control solenoid valve assembly connector C-03. 
    1. Disconnect connector C-03 and measure at the sensor side.
      Fig 8: Locating Transmission Fluid Temperature Sensor At A/T Control Solenoid Valve Connector C-03
      G01850329Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Measure the resistance between terminal 1 and 2.
      • When transmission fluid temperature is 0°C (32°F), resistance should be between 16.7 and 20.5 kohm.
      • When transmission fluid temperature is 20°C (68°F), resistance should be between 7.3 and 8.9 kohm.
      • When transmission fluid temperature is 40°C (104°F), resistance should be between 3.4 and 4.2 kohm.
      • When transmission fluid temperature is 60°C (140°F), resistance should be between 1.9 and 2.2 kohm.
      • When transmission fluid temperature is 80°C (176°F), resistance should be between 1.0 and 1.2 kohm.
      • When transmission fluid temperature is 100°C (212°F), resistance should be between 0.57 and 0.69 kohm.
      Fig 9: Measuring Resistance Between Terminal 1 And 2
      G01850330Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the measured resistance within the specified range? 

    1. YES :  Go to Step 6.
    2. NO :  Replace the transmission fluid temperature sensor. Refer to TRANSMISSION .
  6. STEP 6. Using scan tool MB991502, check data list item 15: Transmission Fluid Temperature Sensor. 
    CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
    1. Connect scan tool MB991502 to the data link connector.
      Fig 10: Connecting Scan Tool MB991502 To Data Link Connector
      G01850331Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Start the engine.
    3. Set scan tool MB991502 to data reading mode for item 15, Transmission Fluid Temperature Sensor.
      • When the engine is cool: Almost equal to the ambient temperature (atmospheric temperature)
        NOTE: Set scan tool MB991502 to data reading mode for item number 13, Intake Air Temperature (IAT) Sensor and note the temperature measurement. When the engine is cool, the temperature should be almost equal to the ambient temperature (atmospheric temperature), and the IAT sensor measurement should be approximately the same as the transmission fluid temperature sensor.
      • When the engine is warm: 70 to 80°C (158 to 176°F)
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the sensor operating properly? 

    1. YES :  It can be assumed that this malfunction is intermittent. Refer to HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS - How to Cope with Intermittent Malfunction.
    2. NO :  Replace the PCM.
  7. STEP 7. Check A/T control solenoid valve assembly connector C-03 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 11: Locating A/T Control Solenoid Valve Assembly Connector C-03
    G01850332Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES :  Go to Step 8.
    2. NO :  Repair or replace the damaged components. Refer to HARNESS CONNECTOR INSPECTION .
  8. STEP 8. Measure the resistance of the ground circuit at A/T control solenoid valve assembly connector C-03. 
    1. Disconnect connector C-03 and measure at the harness side.
      Fig 12: Locating A/T Control Solenoid Valve Assembly Connector C-03
      G01850333Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Measure the resistance between terminal 2 and ground.
      • The resistance should measure less than 2 ohms.
      Fig 13: Measuring Resistance Between Terminal 2 And Ground
      G01850334Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the resistance less than 2 ohms? 

    1. YES :  Go to Step  5 .
    2. NO :  Go to Step  14 .
  9. STEP 9. Measure the sensor output voltage at PCM connector D-135 by backprobing. 
    1. Do not disconnect connector D-135.
      Fig 14: Identifying PCM Connector D-135
      G01850335Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 119 and ground by backprobing.
      • When transmission fluid temperature is 20°C (68°F), voltage should measure between 3.8 and 4.0 volts.
      • When transmission fluid temperature is 40°C (104°F), voltage should measure between 3.2 and 3.4 volts.
      • When transmission fluid temperature is 80°C (176°F), voltage should measure between 1.7 and 1.9 volts.
      Fig 15: Measuring Voltage Between Terminal 119 And Ground By Backprobing
      G01850336Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage within the specified range? 

    1. YES :  Go to Step  12 .
    2. NO :  Go to Step 10.
  10. STEP 10. Check A/T control solenoid valve assembly connector C-03, PCM connector D-135 and intermediate connector E-114 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 16: Locating A/T Control Solenoid Valve Assembly Connector C-03
    G01850337Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 17: Locating PCM Connector D-135
    G01850338Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 18: Locating Intermediate Connector E-114
    G01850339Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connectors and terminals in good condition? 

    1. YES :  Go to Step 11.
    2. NO :  Repair or replace the damaged components. Refer to HARNESS CONNECTOR INSPECTION .
  11. STEP 11. Check the harness for short circuit to ground between A/T control solenoid valve connector C-03 terminal 1 and PCM connector D-135 terminal 119. 
    Fig 19: Identifying A/T Control Solenoid Valve Connector C-03
    G01850340Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 20: Identifying PCM Connector D-135
    G01850341Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES :  Go to Step  6 .
    2. NO :  Repair or replace the harness wire.
  12. STEP 12. Check A/T control solenoid valve assembly connector C-03, PCM connector D-135 and intermediate connector E-114 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 21: Locating A/T Control Solenoid Valve Assembly Connector C-03
    G01850342Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 22: Locating PCM Connector D-135
    G01850343Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 23: Locating Intermediate Connector E-114
    G01850344Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connectors and terminals in good condition? 

    1. YES :  Go to Step 13.
    2. NO :  Repair or replace the damaged components. Refer to HARNESS CONNECTOR INSPECTION .
  13. STEP 13. Check the harness for open circuit between A/T control solenoid valve connector C-03 terminal 1 and PCM connector D-135 terminal 119. 
    Fig 24: Identifying A/T Control Solenoid Valve Connector C-03
    G01850345Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 25: Identifying PCM Connector D-135
    G01850346Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES :  Go to Step  6 .
    2. NO :  Repair or replace the harness wire.
  14. STEP 14. Measure the ground voltage at PCM connector D-135 by backprobing. 
    1. Do not disconnect connector D-135.
      Fig 26: Identifying PCM Connector D-135
      G01850347Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 96 and ground by backprobing.
      • Voltage should measure 0.5 volt or less.
      Fig 27: Measuring Voltage Between Terminal 96 And Ground By Backprobing
      G01850348Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage within the specified range? 

    1. YES :  Go to Step 15.
    2. NO :  Go to Step  17 .
  15. STEP 15. Check A/T control solenoid valve assembly connector C-03, PCM connector D-135 and intermediate connector E-114 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 28: Locating A/T Control Solenoid Valve Assembly Connector C-03
    G01850349Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 29: Locating PCM Connector D-135
    G01850350Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 30: Locating Intermediate Connector E-114
    G01850351Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connectors and terminals in good condition? 

    1. YES :  Go to Step 16.
    2. NO :  Repair or replace the damaged components. Refer to HARNESS CONNECTOR INSPECTION .
  16. STEP 16. Check the harness for open circuit or damage between A/T control solenoid valve connector C-03 terminal 2 and PCM connector D-135 terminal 96. 
    Fig 31: Identifying A/T Control Solenoid Valve Connector C-03
    G01850352Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 32: Identifying PCM Connector D-135
    G01850353Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES :  Go to Step  6 .
    2. NO :  Repair or replace the harness wire.
  17. STEP 17. Check PCM connector D-135 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 33: Locating PCM Connector D-135
    G01850354Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES :  Go to Step  6 .
    2. NO :  Repair or replace the damaged components. Refer to HARNESS CONNECTOR INSPECTION .
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