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Home >> Mitsubishi >> 2010 >> Lancer ES, Standard >> Repair and Diagnosis >> Brakes >> Traction Control >> Active Stability Control System (ASC) -- Lancer >> Diagnosis >> Diagnostic Trouble Code Procedures >> Code No. C101C Abnormality in FR wheel speed sensor signal >> Diagnosis

Code No. C101C Abnormality in FR wheel speed sensor signal: Diagnosis

Required Special Tools: 

  1. STEP 1. Using scan tool MB991958, diagnose the CAN bus lines. 

    Use scan tool to diagnose the CAN bus lines.

    Q: Is the check result normal? 

    1. YES:  Go to Step  3.
    2. NO:  Repair the CAN bus lines (Refer to CAN BUS DIAGNOSTIC TABLE ). On completion, go to Step 2.
  2. STEP 2. DTC recheck after resetting CAN bus lines 

    Q: Is DTC C101C set? 

    1. YES:  Go to Step 3.
    2. NO:  The procedure is complete.
  3. STEP 3. Using scan tool MB991958, check the DTC 

    Check that DTC C1015 is also set.

    Q: Is DTC C1015 also set? 

    1. YES:  Perform the diagnosis for DTC C1015 (Refer to DTC C1015 ABNORMALITY IN FR WHEEL SPEED SENSOR CIRCUIT  ).
    2. NO:  Go to Step 4.
  4. STEP 4. Check for wheel speed sensor installation 

    Check how the wheel speed sensor <FR> is installed (Disconnection of wheel speed sensor, loose mounting bolt, etc.).

    Q: Is the check result normal? 

    1. YES:  Go to Step 5.
    2. NO:  Reinstall the wheel speed sensor <FR> correctly (Refer to <FRONT>  ). Then go to Step  16.
  5. STEP 5. Check for wheel speed sensor as a single unit 

    Refer to WHEEL SPEED SENSOR CURRENT CHECK  .

    Q: Is the check result normal? 

    1. YES:  Go to Step 6.
    2. NO:  Replace the wheel speed sensor <FR> (Refer to <FRONT>  ). Then go to Step  16.
  6. STEP 6. Check for wheel bearing looseness 
    NOTE:
    • Loose wheel bearing may increase the gap between the wheel speed sensor and the wheel speed detection magnet encoder.
    • Check the wheel bearing <FR> for looseness (Refer to ON-VEHICLE SERVICE ).

    Q: Is the check result normal? 

    1. YES:  Go to Step 7.
    2. NO:  Replace the wheel bearing (Refer to FRONT AXLE HUB ASSEMBLY ).
  7. STEP 7. Check of wheel speed detection encoder 

    Check the encoder for adhesion of foreign materials or deformation.

    Q: Is the check result normal? 

    1. YES:  Go to Step 8.
    2. NO (Adhesion of foreign materials):  Remove the foreign materials and clean the encoder so as not to disturb the magnetization pattern on it while taking care of the magnet, magnetic substance, and magnetic attraction.
    3. NO (Deformation):  Replace the wheel bearing (Refer to FRONT AXLE HUB ASSEMBLY ).
      Fig 1: Identifying Magnetic Encoder, Oil Seal And Wheel Bearing
      G06665857Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  8. STEP 8. Voltage measurement at the A-51 ASC-ECU connector 
    1. Disconnect the ASC-ECU connector, connect special tool ASC check harness (MB991997) to the harness-side connector, and then measure the voltage at the special tool connector side.
      NOTE: Do not connect the special tool ASC check harness (MB991997) to ASC-ECU.
    2. Turn the ignition switch to the ON position.
    3. Measure the voltage between the wheel speed sensor power supply terminal (signal terminal) No. 34 and the body ground and between the ground terminal No. 33 and the body ground.

      OK: 1 volt or less 

      Q: Is the check result normal? 

      1. YES:  Go to Step 9.
      2. NO (Not normal at the terminal No. 34 or No. 33):  Go to Step  10.
        Fig 2: Measuring Voltage Between Wheel Speed Sensor Power Supply Terminal No. 34 And Body Ground
        G06665858Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  9. STEP 9. Resistance measurement at A-51 ASC-ECU connector 
    1. Disconnect the ASC-ECU connector, connect special tool ASC check harness (MB991997) to the harness-side connector, and then measure the resistance at the special tool connector side.
      NOTE: Do not connect the special tool ASC check harness (MB991997) to ASC-ECU.
    2. Measure the resistance between the wheel speed sensor power supply terminal (signal terminal) No. 34 and the body ground and between the wheel speed sensor ground terminal No. 33 and the body ground.

      OK: No continuity 

      Q: Is the check result normal? 

      1. YES:  Go to Step  12.
      2. NO (Not normal at the terminal No. 34 or No. 33):  Go to Step 10.
        Fig 3: Measuring Resistance Between Wheel Speed Sensor Power Supply Terminal No. 34 And Body Ground
        G06665859Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  10. STEP 10. Connector check: A-51 ASC-ECU connector, A-02 wheel speed sensor <FR> connector 

    Q: Is the check result normal? 

    1. YES:  Go to Step 11.
    2. NO:  Repair the defective connector. Then go to Step  16.
  11. STEP 11. Wiring harness check between A-51 ASC-ECU connector terminal No. 34 and A-02 wheel speed sensor <FR> connector terminal No. 1 and between A-51 ASC-ECU connector terminal No. 33 and A-02 wheel speed sensor <FR> connector terminal No. 2. 
    • Check for short circuit in wheel speed sensor <FR> circuit.

      Q: Is the check result normal? 

      1. YES:  Go to Step  15.
      2. NO:  Repair the wiring harness. Then go to Step  16.
  12. STEP 12. Voltage measurement at the A-51 ASC-ECU connector 
    1. Disconnect the ASC-ECU connector, connect special tool ASC check harness (MB991997) to the ASC-ECU-side connector and harness-side connector, and then measure the voltage at the special tool connector side.
    2. Turn the ignition switch to the ON position.
    3. Measure the voltage between the wheel speed sensor power supply terminal (signal terminal) No. 34 and body ground, and between the ground terminal No. 33 and body ground.

      OK: Terminal No. 34 and body ground: Battery positive voltage 

      Terminal No. 33 and body ground: 1 volt or less 

      Q: Is the check result normal? 

      1. YES:  Go to Step 13.
      2. NO:  Go to Step  15.
        Fig 4: Measuring Voltage Between Wheel Speed Sensor Power Supply Terminal No. 34 And Body Ground
        G06665860Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  13. STEP 13. Connector check: A-51 ASC-ECU connector, A-02 wheel speed sensor <FR> connector 

    Q: Is the check result normal? 

    1. YES:  Go to Step 14.
    2. NO:  Repair the defective connector. Then go to Step  16.
  14. STEP 14. Wiring harness check between A-51 ASC-ECU connector terminal No. 34 and A-02 wheel speed sensor <FR> connector terminal No. 1 and between A-51 ASC-ECU connector terminal No. 33 and A-02 wheel speed sensor <FR> connector terminal No. 2. 
    • Check for open circuit in wheel speed sensor <FR> circuit.

      Q: Is the check result normal? 

      1. YES:  Go to Step 15.
      2. NO:  Repair the wiring harness. Then go to Step  16.
  15. STEP 15. Check whether the DTC is reset. 
    1. Erase the DTC.
    2. Drive the vehicle at 12 mph (20 km/h) or more.
      NOTE: The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.

      Q: Is DTC C101C set? 

      1. YES:  Replace the hydraulic unit (ASC-ECU) (Refer to HYDRAULIC UNIT  ). Then go to Step 16.
      2. NO:  Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
  16. STEP 16. Check whether the DTC is reset. 
    1. Erase the DTC.
    2. Drive the vehicle at 12 mph (20 km/h) or more.
      NOTE: The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.

      Q: Is DTC C101C set? 

      1. YES:  Return to Step  1.
      2. NO:  The procedure is complete.
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