DTC B1731: Communication Error With The Powertrain Control Module: Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: 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 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? 

      1. YES:  Go to Step 2.
      2. NO:  Repair the CAN bus lines (Refer to PRECAUTIONS ON HOW TO REPAIR THE CAN BUS LINES ).
         Fig 1: Connecting Scan Tool To Data Link Connector

         Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Recheck for diagnostic trouble code. 

   Recheck if the diagnostic trouble code is set.

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

      Q: Is DTC B1731 set? 

      1. YES:  Replace the ETACS-ECU and register the ID codes. (Refer to ENCRYPTED CODE REGISTRATION CRITERIA TABLE  .) After registering the ID codes, go to Step 3.
      2. NO:  The procedure is complete.
         Fig 2: Connecting Scan Tool To Data Link Connector

         Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Recheck for diagnostic trouble code. 

   Recheck if the diagnostic trouble code is set.

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

      Q: Is DTC B1731 set? 

      1. YES:  Replace the powertrain control module and resister the ID code. (Refer to ENCRYPTED CODE REGISTRATION CRITERIA TABLE  .) Retest the system.
      2. NO:  The procedure is complete.
         Fig 3: Connecting Scan Tool To Data Link Connector

         Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.