LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mitsubishi >> 2003 >> Lancer LS >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Diagnostic Trouble Code Procedures - Except Evolution >> DTC >> DTC 21: Crankshaft Position Sensor System >> Diagnosis
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

DTC 21: Crankshaft Position Sensor System: Diagnosis

Required Special Tool: 

  1. MB991502: Scan Tool (MUT-II)
  1. STEP 1. Using scan tool MB991502, check data list item 21: Crankshaft Position 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 To Data Link Connector
      G01876271Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. With the gear selector lever in the "P" position, start the engine and run at idle.
    3. Set scan tool MB991502 to data reading mode for item 21, Crankshaft Position Sensor.
      • When the accelerator pedal is not depressed (throttle valve is fully closed) the display on scan tool MB991502 should be "600 to 900 r/min."
      • With the accelerator pedal depressed, the engine speed display on scan tool MB991502 should increase according to engine speed.

    Q: Does the engine speed display increase according to engine speed when the accelerator pedal is depressed? 

    1. YES:  It can be assumed that this malfunction is intermittent.
    2. NO:  Go to Step 2.
  2. STEP 2. Using the oscilloscope, check the waveform at crankshaft position sensor connector B-117. 
    1. Do not disconnect connector B-117.
      Fig 2: Locating Connector B-117
      G01876272Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Connect an oscilloscope probe between crankshaft position sensor connector B-117 terminal 2 and ground by backprobing.
      Fig 3: Connecting Oscilloscope Probe Between Crankshaft Position Sensor Connector B-117 Terminal 2 & Ground
      G01876273Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    3. With the gear selector lever in the "P" position, start the engine and run at idle.
    4. Check the waveform.
      • The waveform should show a pattern similar to the illustration. The maximum value should be 4.8 volts or more and the minimum value 0.6 volts or less. The output waveform should not contain electrical noise.
      Fig 4: Checking Waveform
      G01876274Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    5. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the waveform normal? 

    1. YES:  Go to Step 3.
    2. NO:  Go to  Step 5 .
  3. STEP 3. Check crankshaft position sensor connector B-117 and PCM connector C-118 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 5: Checking Crankshaft Position Sensor Connector B-117
    G01876275Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 6: Checking PCM Connector C-118
    G01876276Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connectors and terminals in good condition? 

    1. YES:  Go to Step 4.
    2. NO:  Repair or replace the damaged components.
  4. STEP 4. Using scan tool MB991502, check data list item 21: Crankshaft Position 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 7: Connecting Scan Tool To Data Link Connector
      G01876277Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. With the gear selector lever in the "P" position, start the engine and run at idle.
    3. Set scan tool MB991502 to data reading mode for item 21, Crankshaft Position Sensor.
      • When the accelerator pedal is not depressed (throttle valve is fully closed) the display on scan tool MB991502 should be "600 to 900 r/min."
      • With the accelerator pedal depressed, the engine speed display on scan tool MB991502 should increase according to engine speed.

    Q: Does the engine speed display increase according to engine speed when the accelerator pedal is depressed? 

    1. YES:  It can be assumed that this malfunction is intermittent. .
    2. NO:  Replace the PCM.
  5. STEP 5. Check crankshaft position sensor connector B-117 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 8: Checking Crankshaft Position Sensor Connector B-117
    G01876278Courtesy 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.
  6. STEP 6. Measure the sensor output voltage at crankshaft position sensor connector B-117. 
    Fig 9: Measuring Sensor Output Voltage At Crankshaft Position Sensor Connector B-117
    G01876279Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    1. Disconnect connector B-117 and measure at the harness side.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 2 and ground.
      • The voltage should measure between 4.9 and 5.1 volts.
      Fig 10: Measuring Voltage Between Terminal 2 & Ground
      G01876280Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

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

    1. YES:  Go to  Step 12 .
    2. NO:  Go to Step 7.
  7. STEP 7. Measure the sensor output voltage at PCM connector C-118 by backprobing. 
    Fig 11: Measuring Sensor Output Voltage At PCM Connector C-118
    G01876281Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    1. Do not disconnect connector C-118.
    2. Disconnect connector B-117 at the crankshaft position sensor.
    3. Turn the ignition switch to the "ON" position.
    4. Measure the voltage between terminal 45 and ground by backprobing.
      • Voltage should measure between 4.9 and 5.1 volts.
      Fig 12: Measuring Voltage Between Terminal 45 & Ground
      G01876282Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    5. Turn the ignition switch to the "LOCK" (OFF) position.

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

    1. YES:  Go to Step 8.
    2. NO:  Go to  Step 10 .
  8. STEP 8. Check PCM connector C-118 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 13: Checking PCM Connector C-118
    G01876283Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES:  Go to Step 9.
    2. NO:  Repair or replace the damaged components.
  9. STEP 9. Check the harness for open circuit between crankshaft position sensor connector B-117 terminal 2 and PCM connector C-118 terminal 45. 
    Fig 14: Checking Crankshaft Position Sensor Connector B-117 For Open Circuit
    G01876284Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 15: Checking PCM Connector C-118 For Open Circuit
    G01876285Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to  Step 4 .
    2. NO:  Repair or replace the harness wire.
  10. STEP 10. Check PCM connector C-118 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 16: Checking PCM Connector C-118
    G01876286Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES:  Go to Step 11.
    2. NO:  Repair or replace the damaged components.
  11. STEP 11. Check the harness for a short circuit to ground between crankshaft position sensor connector B-117 terminal 2 and PCM connector C-118 terminal 45. 
    Fig 17: Checking Crankshaft Position Sensor Connector B-117 For Short Circuit To Ground
    G01876287Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 18: Checking PCM Connector C-118 For Short Circuit To Ground
    G01876288Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to  Step 4 .
    2. NO:  Repair or replace the harness wire.
  12. STEP 12. Measure the power supply voltage at crankshaft position sensor connector B-117. 
    1. Disconnect connector B-117 and measure at the harness side.
      Fig 19: Disconnecting Connector B-117 & Measuring At Harness Side
      G01876289Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 3 and ground.
      • The voltage should measure battery positive voltage.
      Fig 20: Measuring Voltage Between Terminal 3 & Ground
      G01876290Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

    Q: Is the measured voltage battery positive voltage? 

    1. YES:  Go to  Step 15 .
    2. NO:  Go to Step 13.
  13. STEP 13. Check MFI relay connector B-12X in the engine component relay box for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 21: Checking MFI Relay Connector B-12X
    G01876291Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES:  Go to Step 14.
    2. NO:  Repair or replace the damaged components.
  14. STEP 14. Check the harness for open circuit or short circuit to ground between MFI relay connector B-12X terminal 4 in the engine component relay box and crankshaft position sensor connector B-117 terminal 3. 
    Fig 22: Checking MFI Relay Connector B-12X For Open Circuit Or Short Circuit To Ground
    G01876292Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 23: Checking Crankshaft Position Sensor Connector B-117 For Open Circuit Or Short Circuit To Ground
    G01876293Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to  Step 4 .
    2. NO:  Repair or replace the harness wire.
  15. STEP 15. Measure the resistance of the ground circuit at crankshaft position sensor connector B-117. 
    1. Disconnect connector B-117 and measure at the harness side.
      Fig 24: Disconnecting Connector B-117 & Measuring At Harness Side
      G01876294Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Measure the resistance between terminal 1 and ground.
      • The resistance should measure less than 2 ohms.
      Fig 25: Measuring Resistance Between Terminal 1 & Ground
      G01876295Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the resistance less than 2 ohms? 

    1. YES:  Go to  Step 21 .
    2. NO:  Go to Step 16.
  16. STEP 16. Measure the ground voltage at PCM connector C-120 by backprobing. 
    Fig 26: Measuring Ground Voltage At PCM Connector C-120
    G01876296Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    1. Do not disconnect connector C-120.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 16 and ground by backprobing.
      • The voltage should measure 0.5 volt or less.
      Fig 27: Measuring Voltage Between Terminal 16 & Ground
      G01876297Courtesy 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 17.
    2. NO:  Go to  Step 19 .
  17. STEP 17. Check PCM connector C-120 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 28: Checking PCM Connector C-120
    G01876298Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES:  Go to Step 18.
    2. NO:  Repair or replace the damaged components.
  18. STEP 18. Check the harness for open circuit or damage between crankshaft position sensor connector B-117 terminal 1 and PCM connector C-120 terminal 16. 
    Fig 29: Checking Crankshaft Position Sensor Connector B-117 For Open Circuit Or Damage
    G01876299Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 30: Checking PCM Connector C-120 For Open Circuit Or Damage
    G01876300Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to  Step 4 .
    2. NO:  Repair or replace the harness wire.
  19. STEP 19. Check PCM connector C-120 for loose, corroded or damaged, terminals, or terminals pushed back in the connector. 
    Fig 31: Checking PCM Connector C-120
    G01876301Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connector and terminals in good condition? 

    1. YES:  Go to Step 20.
    2. NO:  Repair or replace the damaged components.
  20. STEP 20. Check the harness for a short circuit to ground between crankshaft position sensor connector B-117 terminal 1 and PCM connector C-120 terminal 16. 
    Fig 32: Checking Crankshaft Position Sensor Connector B-117 For Short Circuit To Ground
    G01876302Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 33: Checking PCM Connector C-120 For Short Circuit To Ground
    G01876303Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to  Step 4 .
    2. NO:  Repair or replace the harness wire.
  21. STEP 21. Check PCM connectors C-120 and C-118, and MFI relay connector B-12X for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 34: Checking PCM Connectors C-120 & C-118
    G01876304Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 35: Checking MFI Relay Connector B-12X
    G01876305Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Are the connectors and terminals in good condition? 

    1. YES:  Go to Step 22.
    2. NO:  Repair or replace the damaged components.
  22. STEP 22. Check the harness for damage between crankshaft position sensor connector B-117 terminal 1 and PCM connector C-120 terminal 16. 
    Fig 36: Checking Crankshaft Position Sensor Connector B-117 For Damage
    G01876306Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 37: Checking PCM Connector C-120 For Damage
    G01876307Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to Step 23.
    2. NO:  Repair or replace the harness wire.
  23. STEP 23. Check the harness for damage between crankshaft position sensor connector B-117 terminal 2 and PCM connector C-118 terminal 45. 
    Fig 38: Checking Crankshaft Position Sensor Connector B-117 For Damage
    G01876308Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 39: Checking PCM Connector C-118 For Damage
    G01876309Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to Step 24.
    2. NO:  Repair or replace the harness wire.
  24. STEP 24. Check the harness for damage between MFI relay connector B-12X terminal 4 in the engine component relay box and crankshaft position sensor connector B-117 terminal 3. 
    Fig 40: Checking MFI Relay Connector B-12X For Damage
    G01876310Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 41: Checking Crankshaft Position Sensor Connector B-117 For Damage
    G01876311Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the harness wire in good condition? 

    1. YES:  Go to Step 25.
    2. NO:  Repair or replace the harness wire.
  25. STEP 25. Check connector B-117-1 for damage. 
    Fig 42: Checking Connector B-117-1 For Damage
    G01876312Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

    Q: Is the connector in good condition? 

    1. YES:  Go to Step 26.
    2. NO:  Repair or replace the damaged components.
  26. STEP 26. Check the crankshaft angle sensing blade. 

    Q: Is the crankshaft angle sensing blade in good condition? 

    1. YES:  Replace the crankshaft position sensor. Refer to Position Sensor Removal and Installation. CRANKSHAFT POSITION SENSOR
    2. NO:  Replace the crankshaft angle sensing blade.
scientia non olet · About LEMON Manuals