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DTC C1201: Front Right Wheel Speed Sensor (Abnormal Output Signal): Diagnosis

Required Special Tools: 

  1. STEP 1. Using scan tool MB991958, diagnose the CAN bus line. 
    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. Turn the ignition switch to the "ON" position.
    3. Diagnose the CAN bus line.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

      Q: Is the CAN bus line found to be normal? 

      YES :  Go to Step  3

      NO :  Repair the CAN bus line (Refer to DIAGNOSIS ). Then go to Step 2.

      Fig 1: Identifying Special Tool MB991910 With Data Link Connector
      G04230562Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  2. STEP 2. Recheck for diagnostic trouble code. 
    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. Turn the ignition switch to the "ON" position.
    2. Erase the DTC.
    3. Turn the ignition switch to the "LOCK" (OFF) position.
    4. Turn the ignition switch to the "ON" position.
    5. Check if the DTC is set.
    6. Turn the ignition switch to the "LOCK" (OFF) position.

      Q: Is DTC C1201 set? 

      YES :  Go to Step 3

      NO :  The procedure is complete.

      Fig 2: Identifying Special Tool MB991910 With Data Link Connector
      G04230562Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  3. STEP 3. Using scan tool MB991958, read the diagnostic trouble code. 
    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.

    Use scan tool MB991958 to check whether DTC C1200 have been set simultaneously.

    1. Connect scan tool MB991958 to the data link connector.
    2. Turn the ignition switch to the "ON" position.
    3. Check whether DTC C1200 have been set.
    4. Turn the ignition switch to the "LOCK" (OFF) position.

      Q: Is DTC C1200 set? 

      YES :  Carry out diagnosis relevant to DTC C1200 (Refer to DTC C1200: FRONT RIGHT WHEEL SPEED SENSOR (OPEN CIRCUIT OR SHORT CIRCUIT)  ).

      NO :  Go to Step 4.

      Fig 3: Identifying Special Tool MB991910 With Data Link Connector
      G04230562Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  4. STEP 4. Check the installation condition of the wheel speed sensors. 

    For the wheel speed sensor, which the DTC indicates, check whether the sensor or its mounting bolts are loosened.

    • DTC C1201 is set: Front right wheel speed sensor

      Q: Is the wheel speed sensor installed correctly? 

      YES :  Go to Step 5.

      NO :  Reinstall the wheel speed sensor correctly (Refer to WHEEL SPEED SENSOR  ). Then go to Step  13.

  5. STEP 5. Check the wheel speed sensor after it is removed from the vehicle. 

    Check the wheel speed sensor which the DTC indicates. Refer to INSPECTION .

    • DTC C1201 is set: Front right wheel speed sensor

      Q: Is the wheel speed sensor in good condition? 

      YES :  Go to Step 6.

      NO :  Replace the wheel speed sensor (Refer to WHEEL SPEED SENSOR  ). Then go to Step  14.

  6. STEP 6. Check the wheel bearing for looseness. 
    NOTE: If the wheel bearing is loose, the gap between the wheel speed sensor and rotor may become excessive. Check the wheel bearing, which DTC indicates, for looseness.
    • DTC C1201 is set: Check the front right wheel bearing (Refer to WHEEL BEARING END PLAY CHECK .

      Q: Is the wheel bearing end play within the standard value? 

      YES :  Go to Step 7.

      NO :  Replace the front hub assembly (Refer to FRONT AXLE HUB ASSEMBLY ).

  7. STEP 7. Check the wheel speed rotor. 

    Check the wheel speed rotor, which DTC indicates, for foreign material or deformation.

    • DTC C1201 is set: Front right wheel speed sensor

      Q: Is the wheel speed rotor in good condition? 

      YES :  Go to Step 8.

      NO :  If the wheel speed rotor is contaminated with foreign material, clean it. If the driveshaft is deformed, replace it (Refer to DRIVE SHAFT ASSEMBLY ).

  8. STEP 8. Measure the voltage at ABS/TCL-ECU connector A-03. 
    1. Disconnect the connector A-03, and connect special tool MB991997 to the wiring harness-side connector.
      NOTE: Do not connect special tool MB991997 to the ABS/TCL-ECU.
    2. Turn the ignition switch to the "ON" position.
    3. Measure the voltage between terminal 33 and body ground, and between terminal 34 and body ground. It should be 1V or less.

      Q: Does the voltage measure 1 V or less? 

      YES :  Go to Step 9.

      NO :  Go to Step  12.

      Fig 4: Measuring Resistance Between Terminal 33 And Body Ground
      G05892084Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  9. STEP 9. Measure the resistance at ABS/TCL-ECU connector A-03. 
    1. Disconnect the connector A-03, and connect special tool MB991997 to the wiring harness-side connector.
      NOTE: Do not connect special tool MB991997 to the ABS/TCL-ECU.
    2. Measure the resistance between terminal 33 and body ground, and between terminal 34 and body ground. There should be no continuity.

      Q: Does continuity exist? 

      YES :  Go to Step  12.

      NO :  Go to Step 10.

      Fig 5: Measuring Resistance Between Terminal 33 And Body Ground
      G05892084Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  10. STEP 10. Measure the resistance at ABS/TCL-ECU connector A-03. 
    1. Disconnect the connector A-03, and connect special tool MB991997 to the wiring harness-side connector.
      NOTE: Do not connect special tool MB991997 to the ABS/TCL-ECU.
    2. Measure the resistance between terminal 33 and 34.

      Standard Value: 1.24 - 1.64 kΩ 

      Q: Is the resistance between terminals 33 and 34 within the standard value? 

      YES :  Go to Step  13.

      NO :  Go to Step 11.

      Fig 6: Measuring Resistance Between ABS/TCL-ECU Connector Terminals 33 And 34
      G05892086Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  11. STEP 11. Inspect the wheel speed sensor. 

    Check the front right wheel speed sensor relevant to the DTC. For the applicable inspection procedure, refer to TRACTION CONTROL SYSTEM (TCL) DIAGNOSIS  .

    Q: Is the wheel speed sensor damaged? 

    YES :  Replace the wheel speed sensor (Refer to WHEEL SPEED SENSOR  ).

    NO :  Go to Step 12.

  12. STEP 12. Check ABS/TCL-ECU connector A-03 and wheel speed sensor < front: RH > connector A-01 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

    Q: Are ABS/TCL-ECU connector A-03 and wheel speed sensor < front: RH > connector A-01 damaged? 

    YES :  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Then go to Step  14.

    NO :  Open or short circuit may be present in the front right wheel speed sensor circuit. Repair the wiring harness between ABS/TCL-ECU connector A-03 (terminals 33 and 34) and front right wheel speed sensor A-01 (terminals 1 and 2). Then go to Step  14.

    Fig 7: Identifying Wheel Speed Sensor Front RH Connector A-01
    G05892087Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    Fig 8: Locating ABS/TCL-ECU Connector A-03
    G04232263Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  13. STEP 13. Recheck for diagnostic trouble code. 
    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.

    Check again if the DTC is set.

    1. Turn the ignition switch to the "ON" position.
    2. Erase the DTC.
    3. Turn the ignition switch to the "LOCK" (OFF) position.
    4. Turn the ignition switch to the "ON" position.
    5. Check if the DTC is set.
    6. Turn the ignition switch to the "LOCK" (OFF) position.

      Q: Is DTC C1201 set? 

      YES :  Replace the hydraulic unit (integrated with ABS/TCL-ECU). Then go to Step 14.

      NO :  It can be assumed that this malfunction is intermittent. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

      Fig 9: Identifying Special Tool MB991910 With Data Link Connector
      G04230562Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  14. STEP 14. Recheck for diagnostic trouble code. 
    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.

    Check again if the DTC is set.

    1. Turn the ignition switch to the "ON" position.
    2. Erase the DTC.
    3. Turn the ignition switch to the "LOCK" (OFF) position.
    4. Turn the ignition switch to the "ON" position.
    5. Check if the DTC is set.
    6. Turn the ignition switch to the "LOCK" (OFF) position.

      Q: Is DTC C1201 set? 

      YES :  Go to Step  1.

      NO :  The procedure is complete.

      Fig 10: Identifying Special Tool MB991910 With Data Link Connector
      G04230562Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
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