DTC C101F: Mutual monitoring of FR wheel speed sensor: 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. 

   Using scan tool MB991958, diagnose the CAN bus lines.

   Q: Is the check result normal? 

   YES  : Go to Step  3.

   NO  : Repair the CAN bus lines. (Refer to TROUBLESHOOTING .) After repairing the CAN bus line, go to Step 2.

2. STEP 2. DTC recheck after repairing the CAN bus line 

   Q: Is DTC C101F set? 

   YES  : Go to Step 3.

   NO  : This diagnosis is complete.

3. STEP 3. Scan tool diagnostic trouble code 

   Check if DTC No. C1015 is also set.

   Q: Is DTC C1015 also set? 

   YES  : Carry out the diagnosis for code No. C1015. (Refer to DTC C1015: ABNORMALITY IN FR WHEEL SPEED SENSOR CIRCUIT  .)

   NO  : Go to Step 4.

4. STEP 4. Check of wheel speed sensor installation status 

   Check the installation status of wheel speed sensor < FR > (disconnection of wheel speed sensor, looseness of mounting bolt, etc.).

   Q: Is the check result normal? 

   YES  : Go to Step 5.

   NO  : Reinstall the wheel speed sensor < FR > correctly. (Refer to WHEEL SPEED SENSOR  .) Then go to Step  9.

5. STEP 5. Check of wheel speed sensor as a single unit 

   Refer to WHEEL SPEED SENSOR CURRENT CHECK  .

   Q: Is the check result normal? 

   YES  : Go to Step 6.

   NO  : Replace the wheel speed sensor < FR >. (Refer to WHEEL SPEED SENSOR  .) Then go to Step  9.

6. STEP 6. Wheel bearing looseness check 
   NOTE: Wheel bearing looseness 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? 

   YES  : Go to Step 7.

   NO  : Replace the front hub assembly. (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.

   Fig 1: Identifying Oil Seal, Hub, Magnetic Encoder And Wheel Bearing

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

   Q: Is the check result normal? 

   YES  : Go to Step 8.

   NO (Adhesion of foreign materials)  : Clean the encoder so as not to disturb the magnetization pattern on the encoder while taking care of the magnet, magnetic substance, and magnetic attraction.

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

8. STEP 8. Check whether the DTC is reset. 
   1. Erase the diagnostic trouble code.
   2. Drive the vehicle at 12mph (20 km/h) or more.
      NOTE: The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12mph (20 km/h) or higher.

   Q: Is DTC C101F set? 

   YES  : Replace the hydraulic unit (incorporates in ASC-ECU).(Refer to HYDRAULIC UNIT  .) Then go to Step 9.

   NO  : Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .)

9. STEP 9. Check whether the DTC is reset. 
   1. Erase the diagnostic trouble code.
   2. Drive the vehicle at 12mph (20 km/h) or more.
      NOTE: The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12mph (20 km/h) or higher.

   Q: Is DTC C101F set? 

   YES  : Return to Step  1.

   NO  : This diagnosis is complete.