DTC C1042 Abnormality in periodical signal for 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

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 C1042 set? 

   1. YES:  Go to Step 3.
   2. NO:  The procedure is complete.
3. STEP 3. 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 4.
   2. NO:  Replace the wheel bearing (Refer to DISASSEMBLY AND ASSEMBLY ).
4. STEP 4. 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 5.
   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. When the encoder is deformed, replace the wheel bearing.
   3. NO (Deformation):  Replace the wheel bearing (Refer to DISASSEMBLY AND ASSEMBLY ).
      Fig 1: Identifying Magnetic Encoder, Oil Seal And Wheel Bearing

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
5. STEP 5. 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 C1042 set? 

      1. YES:  Replace the hydraulic unit (ASC-ECU) (Refer to HYDRAULIC UNIT  ). Then go to Step 6.
      2. NO:  Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
6. STEP 6. 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 C1042 set? 

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