DTC P1766 (P0715): Input Shaft Speed Sensor System (Short Circuit/Open Circuit): Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: V.C.I.
  • MB991827: M.U.T.-III USB Cable
  • MB991910: M.U.T.-III Main Harness A

1. STEP 1. Using scan tool MB991958, check data list item 5: Input Shaft Speed Sensor. 
   CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
   1. Connect scan tool MB991958 to the data link connector.
   2. Start the engine.
   3. Set scan tool MB991958 to data reading mode.
      • Item 5: Input Shaft Speed Sensor.
        • When driving at constant speed of 50 km/h (31 mph), the display should be "1,500 - 1,800 r/min" (Gear range: 3rd gear). <4A/T>
        • When driving at constant speed of 60 km/h (37 mph), the display should be "1,400 - 1,700 r/min" (Gear range: 4th gear). <5A/T>
   4. Turn the ignition switch to the "LOCK" (OFF) position.
      Fig 1: Connecting Special Tool MB991910 To Data Link Connector

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

      Q: Is the sensor operating properly? 

      1. YES:  It can be assumed that this malfunction is intermittent. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .
      2. NO:  Go to Step 2.
2. STEP 2. Measure the power supply voltage at the input shaft speed sensor connector B-112. 
   1. Disconnect connector B-112 and measure at the harness side.
   2. Turn the ignition switch to the "ON" position.
      Fig 2: Locating Input Shaft Speed Sensor Connector B-112

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   3. Measure the voltage between terminal 3 and ground.
      • The voltage should measure battery positive voltage.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

      Q: Is the measured voltage battery positive voltage? 

      1. YES:  Go to Step  5.
      2. NO:  Go to Step 3.
         Fig 3: Measuring Voltage Between Terminal 3 And Ground

         Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Check intermediate connector A-15, C-24, joint connector (1) C-28 and junction block connector C-203 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Are the connectors and terminals in good condition? 

   1. YES:  Go to Step 4.
   2. NO:  Repair or replace the damaged components. Refer to HARNESS CONNECTOR INSPECTION .
      Fig 4: Locating Intermediate Connector A-15

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      Fig 5: Locating Intermediate Connector C-24

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      Fig 6: Locating Joint Connector C-28

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      Fig 7: Locating Junction Block Connector C-203

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4. STEP 4. Check the harness for open circuit or short circuit to ground between the input shaft speed sensor connector B-112 terminal 3 and the junction block connector C-203 terminal 12. 

   Q: Is the harness wire in good condition? 

   1. YES:  Go to Step 5.
   2. NO:  Repair or replace the harness wire.
      Fig 8: Locating Input Shaft Speed Sensor Connector B-112

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      Fig 9: Locating Junction Block Connector C-203

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
5. STEP 5. Measure the PCM to speed sensor output voltage at the input shaft speed sensor connector B-112. 
   1. Disconnect connector B-112 from the speed sensor and measure voltage at the harness side.
   2. Turn the ignition switch to the "ON" position.
      Fig 10: Locating Input Shaft Speed Sensor Connector B-112

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   3. Measure the voltage between terminal 2 and ground.
      • The voltage should measure between 4.5 and 4.9 volts.
   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  11.
      2. NO:  Go to Step 6.
         Fig 11: Measuring Voltage Between Terminal 2 And Ground

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6. STEP 6. Measure the PCM output voltage to the speed sensor at the PCM connector B-21 by using check harness special tool MB991923. 
   1. Disconnect all the connectors from the PCM.
      Fig 12: Locating PCM Connector B-21

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   2. Connect special tool MB991923 (check harness) between the PCM and the body-side harness connector.
   3. Turn the ignition switch to the "ON" position.
      Fig 13: Connecting Special Tool MB991923 (Check Harness) Between PCM And Body-Side Harness Connector

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   4. Measure the voltage between PCM terminal 111 and ground.
      • The voltage should measure between 4.5 and 4.9 volts.
   5. 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 7.
      2. NO:  Go to Step  9.
         Fig 14: Measuring Voltage Between PCM Terminal 111 And Ground

         Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
7. STEP 7. Check PCM connector B-21 and input shaft speed sensor connector B-112 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Are the connectors in good condition? 

   1. YES:  Go to Step 8.
   2. NO:  Repair or replace the damaged components. Refer to HARNESS CONNECTOR INSPECTION .
      Fig 15: Locating PCM Connector B-21

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      Fig 16: Locating Input Shaft Speed Sensor Connector B-112

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
8. STEP 8. Check the harness for open circuit or damage between PCM connector B-21 terminal 111 and input shaft speed sensor connector B-112 terminal 2. 

   Q: Is the harness wire in good condition? 

   1. YES:  Go to Step  19.
   2. NO:  Repair or replace the harness wire.
      Fig 17: Locating PCM Connector B-21

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      Fig 18: Locating Input Shaft Speed Sensor Connector B-112

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
9. STEP 9. Check PCM connector B-21 and input shaft speed sensor connector B-112 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Are the connectors and terminals in good condition? 

   1. YES:  Go to Step 10.
   2. NO:  Repair or replace the damages components. Refer to HARNESS CONNECTOR INSPECTION .
      Fig 19: Locating PCM Connector B-21

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
      Fig 20: Locating Input Shaft Speed Sensor Connector B-112

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10. STEP 10. Check the harness for short circuit to ground between PCM connector B-21 terminal 111 and input shaft speed sensor connector B-112 terminal 2. 

    Q: Is the harness wire in good condition? 

    1. YES:  Go to Step 11.
    2. NO:  Repair or replace the harness wire.
       Fig 21: Locating PCM Connector B-21

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
       Fig 22: Locating Input Shaft Speed Sensor Connector B-112

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11. STEP 11. Measure the ground circuit for resistance at the input shaft speed sensor connector B-112. 
    1. Disconnect connector B-112 from the speed sensor and measure at the harness side.
       Fig 23: Locating Input Shaft Speed Sensor Connector B-112

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Measure the resistance between terminal 1 and ground.
       • The resistance should measure less than 2 ohms.

       Q: Is the measured resistance less than 2 ohms? 

       1. YES:  Go to Step  16.
       2. NO:  Go to Step 12.
          Fig 24: Measuring Resistance Between Terminal 1 And Ground

          Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
12. STEP 12. Measure the resistance at the PCM connector B-21 by using check harness special tool. 
    1. Disconnect all the connectors from the PCM.
       Fig 25: Locating PCM Connector B-21

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Connect special tool MB991923 (check harness) between the PCM and the body-side harness connector.
    3. Turn the ignition switch to the "ON" position.
       Fig 26: Connecting Special Tool MB991923 (Check Harness) Between PCM And Body-Side Harness Connector

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Measure the resistance between terminal 113 and ground.
       • The resistance should measure less than 2 ohms.
    5. Turn the ignition switch to the "LOCK" (OFF) position.

       Q: Is the measured resistance less than 2 ohms? 

       1. YES:  Go to Step 13.
       2. NO:  Go to Step  15.
          Fig 27: Measuring Resistance Between Terminal 113 And Ground

          Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
13. STEP 13. Check PCM connector B-21 and input shaft speed sensor connector B-112 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

    Q: Are the connectors and terminals in good condition? 

    1. YES:  Go to Step 14.
    2. NO:  Repair or replace the damaged components. Refer to HARNESS CONNECTOR INSPECTION .
       Fig 28: Locating PCM Connector B-21

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
       Fig 29: Locating Input Shaft Speed Sensor Connector B-112

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14. STEP 14. Check the harness for open circuit or damage between PCM connector B-21 terminal 113 and input shaft speed sensor connector B-112 terminal 1. 

    Q: Is the harness wire in good condition? 

    1. YES:  Go to Step  16.
    2. NO:  Repair or replace the harness wire.
       Fig 30: Locating PCM Connector B-21

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
       Fig 31: Locating Input Shaft Speed Sensor Connector B-112

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
15. STEP 15. Check PCM connector B-21 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

    Q: Are the connector and terminals in good condition? 

    1. YES:  Replace the PCM. When the PCM is replaced, register the encrypted code. Refer to ENCRYPTED CODE REGISTRATION CRITERIA TABLE .
    2. NO:  Repair or replace the damaged components. Refer to HARNESS CONNECTOR INSPECTION .
       Fig 32: Locating PCM Connector B-21

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
16. STEP 16. Using the oscilloscope, check the input shaft speed sensor waveform at PCM connectors B-21 by using check harness special tool MB991923. 
    1. Disconnect all the connectors from the PCM.
       Fig 33: Locating PCM Connector B-21

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Connect special tool MB991923 (check harness) between the PCM and the body-side harness connector.
       Fig 34: Connecting Special Tool MB991923 (Check Harness) Between PCM And Body-Side Harness Connector

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    3. Connect an oscilloscope probe to PCM connector B-21 terminal 111 and to 113.
    4. Start the engine and drive the vehicle at constant speed of 50 km/h (31 mph) (Gear range: 3rd gear) <4A/T> or 60 km/h (37 mph) (Gear range: 4th gear) <5A/T>.
       Fig 35: Connecting Oscilloscope Probe To PCM Connector B-21 Terminal 111 And To 113

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    5. Check the input shaft speed sensor waveform.
       • The input shaft speed sensor waveform should show a pattern similar to the illustration. The maximum value should be 4.8 volts or more and the minimum value 0.8 volt or less. The output waveform should not contain electrical noise.
    6. Turn the ignition switch to the "LOCK" (OFF) position.

       Q: Is the waveform normal? 

       1. YES:  Go to Step  19.
       2. NO:  Go to Step 17.
          Fig 36: Input Shaft Speed Sensor Waveform

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17. STEP 17. Replace the input shaft speed sensor. 
    1. Replace the input shaft speed sensor. Refer to TRANSAXLE <4A/T> or Refer to TRANSAXLE <5A/T>.
    2. Test drive the vehicle.
    3. Check for A/T diagnostic trouble code.

       Q: Is A/T DTC P1766 set? 

       1. YES:  Go to Step 18.
       2. NO:  The procedure is complete.
          Fig 37: Locating Input Shaft Speed Sensor

          Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
18. STEP 18. Replace the underdrive clutch retainer. 
    1. Replace the underdrive clutch retainer. Refer to UNDERDRIVE CLUTCH AND INPUT SHAFT <4A/T> or Refer to UNDERDRIVE CLUTCH AND INPUT SHAFT <5A/T>.
    2. Test drive the vehicle.
    3. Check for A/T diagnostic trouble code.

       Q: Is A/T DTC P1766 set? 

       1. YES:  An A/T DTC may have set due to external radio frequency interference (RFI) possibly caused by cellular phone activity, or aftermarket components installed on the vehicle.
       2. NO:  The procedure is complete.
          Fig 38: Locating Underdrive Clutch Retainer

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19. STEP 19. Using scan tool MB991958, check data list item 5: Input Shaft Speed Sensor. 
    CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
    1. Connect scan tool MB991958 to the data link connector.
    2. Start the engine.
    3. Set scan tool MB991958 to data reading mode.
       • Item 5: Input Shaft Speed Sensor.
         • When driving at constant speed of 50 km/h (31 mph), the display should be "1,500 - 1,800 r/min" (Gear range: 3rd gear). <4A/T>
         • When driving at constant speed of 60 km/h (37 mph), the display should be "1,400 - 1,700 r/min" (Gear range: 4th gear). <5A/T>
    4. Turn the ignition switch to the "LOCK" (OFF) position.
       Fig 39: Connecting Special Tool MB991910 To Data Link Connector

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

       Q: Is the sensor operating properly? 

       1. YES:  It can be assumed that this malfunction is intermittent. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .
       2. NO:  Replace the PCM. When the PCM is replaced, register the encrypted code. Refer to ENCRYPTED CODE REGISTRATION CRITERIA TABLE .