DTC 12: TP Sensor System (Open Circuit): Diagnosis

Required Special Tool: 

• MB991502: Scan Tool (MUT-II)

1. STEP 1. Using scan tool MB991502, check data list item 11: TP 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

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   2. Turn the ignition switch to the "ON" position.
   3. Set scan tool MB991502 to data-reading mode for item 11, TP Sensor.
      • With the throttle valve in the idle position, voltage should measure between 300 and 1,000 mV <3.0L Engine>, 535 and 735 mV <3.5L Engine>.
      • With the throttle valve in the full-open position, voltage should measure between 4,500 and 5,500 mV.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the measured voltage between 300 and 1,000 mV <3.0L Engine> or 535 and 735mV <3.5L Engine> at idle, and between 4,500 and 5,500 mV in the full-open position? 

   YES:  It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

   NO:  Go to Step 2.

2. STEP 2. Measure the sensor output voltage at TP sensor connector A-41 by backprobing. 
   1. Do not disconnect connector A-41.
      Fig 2: Locating TP Sensor Connector A 41 & Terminal Identification

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   2. Turn the ignition switch to the "ON" position.
   3. Measure the voltage between terminal 3 and ground by backprobing.
      • With the throttle valve in the idle position, voltage should measure between 0.3 and 1.0 volt <3.0L Engine>, 0.535 and 0.735 volt <3.5L Engine>.
      • With the throttle valve in the full-open position, voltage should measure between 4.5 and 5.5 volts.
      Fig 3: Measuring Voltage Between Terminal 3 And Ground By Backprobing

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   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the measured voltage between 0.3 and 1.0 volt <3.0L Engine> or 0.535 and 0.735 volt <3.5L Engine> at idle, and between 4.5 and 5.5 volts in the full-open position? 

   YES:  Go to Step 3.

   NO:  Go to Step  8.

3. STEP 3. Measure the TP sensor output voltage at PCM connector C-91 by backprobing. 
   1. Do not disconnect connector C-91.
      Fig 4: Locating PCM Connector C 91 & Terminal Identification

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   2. Turn the ignition switch to the "ON" position.
   3. Measure the voltage between terminal 78 and ground by backprobing.
      • With the throttle valve in the idle position, voltage should measure between 0.3 and 1.0 volt <3.0L Engine>, 0.535 and 0.735 volt <3.5L Engine>.
      • With the throttle valve in the full-open position, voltage should measure between 4.5 and 5.5 volts.
      Fig 5: Measuring Voltage Between Terminal 78 And Ground By Backprobing

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the measured voltage between 0.3 and 1.0 volt <3.0L Engine> or 0.535 and 0.735 volt <3.5L Engine> at idle, and between 4.5 and 5.5 volts in the full-open position? 

   YES:  Go to Step 4.

   NO:  Go to Step  6.

4. STEP 4. Check TP sensor connector A-41 and PCM C-91 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
   Fig 6: Locating TP Sensor Connector A 41 & Terminal Identification

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   Fig 7: Locating PCM Connector C 91 & Terminal Identification

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   Q: Are the connectors and terminals in good condition? 

   YES:  Go to Step 5.

   NO:  Repair or replace the damaged components. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

5. STEP 5. Using scan tool MB991502, check data list item 11: TP 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 8: Connecting Scan Tool MB991502 To Data Link Connector

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   2. Turn the ignition switch to the "ON" position.
   3. Set scan tool MB991502 to data-reading mode for item 11, TP Sensor.
      • With the throttle valve in the idle position, voltage should measure between 300 and 1,000 mV <3.0L Engine>, 535 and 735 mV <3.5L Engine>.
      • With the throttle valve in the full-open position, voltage should measure between 4,500 and 5,500 mV.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the measured voltage between 300 and 1,000 mV <3.0L Engine> or 535 and 735 mV <3.5L Engine> at idle, and between 4,500 and 5,500 mV in the full-open position? 

   YES:  It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

   NO:  Replace the PCM.

6. STEP 6. Check TP sensor A-41 and PCM connector C-91 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
   Fig 9: Locating TP Sensor Connector A 41 & Terminal Identification

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   Fig 10: Locating PCM Connector C 91 & Terminal Identification

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   Q: Are the connectors and terminals in good condition? 

   YES:  Go to Step 7.

   NO:  Repair or replace the damaged components. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

7. STEP 7. Check the harness for open circuit or damage between TP sensor connector A-41 terminal 3 and PCM connector C-91 terminal 78. 
   Fig 11: Locating TP Sensor Connector A 41 & Terminal Identification

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   Fig 12: Locating PCM Connector C 91 & Terminal Identification

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   Q: Is the harness wire in good condition? 

   YES:  Go to Step  5.

   NO:  Repair or replace the harness wire.

8. STEP 8. Measure the power supply voltage from the PCM at TP sensor connector A-41 by backprobing. 
   1. Do not disconnect connector A-41.
      Fig 13: Locating TP Sensor Connector A 41 & Terminal Identification

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   2. Turn the ignition switch to the "ON" position.
   3. Measure the voltage between terminal 4 and ground by backprobing.
      • The voltage should measure between 4.9 and 5.1 volts.
      Fig 14: Measuring Voltage Between Terminal 4 And Ground By Backprobing

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   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the measured voltage between 4.9 and 5.1 volts? 

   YES:  Go to Step  14.

   NO:  Go to Step 9.

9. STEP 9. Measure the power supply voltage at PCM connector C-90 by backprobing. 
   1. Do not disconnect connector C-90.
      Fig 15: Locating PCM Connector C 90 & Terminal Identification

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   2. Turn the ignition switch to the "ON" position.
   3. Measure the voltage between terminal 46 and ground by backprobing.
      • The voltage should measure between 4.9 and 5.1 volts.
      Fig 16: Measuring Voltage Between Terminal 46 And Ground By Backprobing

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   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the measured voltage between 4.9 and 5.1 volts? 

   YES:  Go to Step 10.

   NO:  Go to Step  12.

10. STEP 10. Check TP sensor connector A-41 and PCM connector C-90 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 17: Locating TP Sensor Connector A 41 & Terminal Identification

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    Fig 18: Locating PCM Connector C 90 & Terminal Identification

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    Q: Are the connectors and terminals in good condition? 

    YES:  Go to Step 11.

    NO:  Repair or replace the damaged components. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

11. STEP 11. Check the harness for open circuit or damage between TP sensor connector A-41 terminal 4 and PCM connector C-90 terminal 46. 
    Fig 19: Locating TP Sensor Connector A 41 & Terminal Identification

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    Fig 20: Locating PCM Connector C 90 & Terminal Identification

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    Q: Is the harness wire in good condition? 

    YES:  Go to Step  5.

    NO:  Repair or replace the harness wire.

12. STEP 12. Check TP sensor connector A-41 and PCM connector C-90 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 21: Locating TP Sensor Connector A 41 & Terminal Identification

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    Fig 22: Locating PCM Connector C 90 & Terminal Identification

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    Q: Are the connectors and terminals in good condition? 

    YES:  Go to Step 13.

    NO:  Repair or replace the damaged components. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

13. STEP 13. Check harness for short circuit to ground between TP sensor connector A-41 terminal 4 and PCM connector C-90 terminal 46. 
    Fig 23: Locating TP Sensor Connector A 41 & Terminal Identification

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    Fig 24: Locating PCM Connector C 90 & Terminal Identification

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    Q: Is harness wire in good condition? 

    YES:  Go to Step  5.

    NO:  Repair or replace the harness wire.

14. STEP 14. Check TP sensor connector A-41 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 25: Locating TP Sensor Connector A 41 & Terminal Identification (Damage Inspection)

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    Q: Are the connector and terminals in good condition? 

    YES:  Go to Step 15.

    NO:  Repair or replace the damaged components. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

15. STEP 15. Measure the TP sensor. 
    1. Disconnect connector A-41 and measure at the TP sensor side.
       Fig 26: Locating TP Sensor Connector A 41 & Terminal Identification

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    2. Measure the resistance between TP sensor connector terminal 1 and 4.

       Specified resistance: 3.5 - 6.5 kΩ 

       Fig 27: Measuring Resistance Between TP Sensor Connector Terminal 1 And 4

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    3. Measure the resistance between the TP sensor side connector terminal 1 and 3.
       Fig 28: Measuring Resistance Between The TP Sensor Side Connector Terminal 1 And 3

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    4. Move the throttle valve from the idle position to the full-open position.
       • The resistance should change smoothly in proportion to the opening angle of the throttle valve.

    Q: Does the resistance change smoothly between 3.5 - 6.5 kΩ in proportion to the opening angle of the throttle valve? 

    YES:  Go to Step 16.

    NO:  Replace the TP sensor. Refer to THROTTLE POSITION SENSOR .

16. STEP 16. Check PCM connectors C-90 and C-91 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 29: Locating PCM Connector C 90 And C 91 & Terminal Identification

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    Q: Are the connectors and terminals in good condition? 

    YES:  Go to Step 17.

    NO:  Repair or replace the damaged components. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

17. STEP 17. Check harness for a short circuit to ground or damage between TP sensor connector A-41 terminal 3 and PCM connector C-91 terminal 78. 
    Fig 30: Locating TP Sensor Connector A 41 & Terminal Identification

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    Fig 31: Locating PCM Connector C 91 & Terminal Identification

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    Q: Is the harness wire in good condition? 

    YES:  Go to Step 18.

    NO:  Repair or replace the harness wire.

18. STEP 18. Check the TP sensor connector and harness for a short circuit to ground between the TP sensor connector and the auto-cruise control-ECU connector. 

    Q: Are the connector and harness wire in good condition? 

    YES:  Adjust the TP sensor. Refer to THROTTLE POSITION SENSOR & CLOSED THROTTLE POSITION SWITCH .

    NO:  Repair or replace the damaged components.