DTC C1015: Abnormality in FR wheel speed sensor circuit: Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: Vehicle Communication Interface (V.C.I.)
  • MB991827: M.U.T.-III USB Cable
  • MB991910: M.U.T.-III Main Harness A
• MB991997: ASC check harness

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 DIAGNOSTICS TABLE ). On completion, go to Step 2.
2. STEP 2. DTC recheck after resetting CAN bus lines 

   Q: Is DTC C1015 set? 

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

   Check the following data list (Refer to DATA LIST REFERENCE TABLE  ).

   • Item No. 02: FR wheel speed sensor

   Q: Is the check result normal? 

   1. YES:  Go to  Step 10.
   2. NO:  Go to Step 4.
4. STEP 4. Connector check: A-51 ASC-ECU connector, A-02 front wheel speed sensor < RH > connector 

   Q: Is the check result normal? 

   1. YES:  Go to Step 5.
   2. NO:  Repair the defective connector. Then go to  Step 11.
5. STEP 5. 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 to ASC-ECU.
   2. Turn the ignition switch to the ON position.
   3. Measure the voltage between the front wheel speed sensor < RH > 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 6.
   2. NO (Not normal at the terminal No. 34 or No. 33):  Go to  Step 8.
      Fig 1: Measuring Voltage Between Front Wheel Speed Sensor Power Supply Terminal And Body Ground

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
6. STEP 6. 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 to ASC-ECU.
   2. Measure the resistance between the front wheel speed sensor < RH > power supply terminal (signal terminal) No. 34 and the body ground and between the front wheel speed sensor < RH > ground terminal No. 33 and the body ground.

      OK: No continuity 

   Q: Is the check result normal? 

   1. YES:  Go to Step 7.
   2. NO (Not normal at the terminal No. 34 or No. 33):  Go to  Step 8.
      Fig 2: Measuring Resistance Between Front Wheel Speed Sensor Power Supply Terminal And Body Ground

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
7. STEP 7. 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 front wheel speed sensor < RH > 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 8.
   2. NO:  Go to  Step 10.
      Fig 3: Measuring Voltage Between Front Wheel Speed Sensor Power Supply Terminal And Body Ground

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
8. STEP 8. Check for wheel speed sensor < FR > as a single unit 

   Refer to WHEEL SPEED SENSOR  .

   Q: Is the check result normal? 

   1. YES:  Go to Step 9.
   2. NO:  Replace the wheel speed sensor < FR > (Refer to WHEEL SPEED SENSOR  ). Then go to  Step 11.
9. STEP 9. Wiring harness check between A-51 ASC-ECU connector terminal No. 34 and A-02 front wheel speed sensor < RH > connector terminal No. 1 and between A-51 ASC-ECU connector terminal No. 33 and A-02 front wheel speed sensor < RH > connector terminal No. 2. 
   • Check for the open or short circuit in front wheel speed sensor < RH > circuit.

   Q: Is the check result normal? 

   1. YES:  Go to Step 10.
   2. NO:  Repair the wiring harness. Then go to  Step 11.
10. STEP 10. Check whether the DTC is reset. 
    1. Erase the DTC.
    2. Drive the vehicle at 12 mph (20 km/h) or higher.
       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 C1015 set? 

    1. YES:  Replace the hydraulic unit (ASC-ECU) (Refer to HYDRAULIC UNIT  ). Then go to Step 11.
    2. NO:  Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).
11. STEP 11. Check whether the DTC is reset. 
    1. Erase the DTC.
    2. Drive the vehicle at 12 mph (20 km/h) or higher.
       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 C1015 set? 

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