DTC U1073: Bus off: 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. 

   Use scan tool MB991958 to diagnose the CAN bus lines.

   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 "ON" position.
   3. Diagnose the CAN bus line.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the check result satisfactory? 

   YES:  Go to Step  2.

   NO:  Repair the CAN bus lines. (Refer to CAN BUS DIAGNOSTIC CHART ).

   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 "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 the check result satisfactory? 

   YES:  An intermittent malfunction is suspected. Refer to "How to Use Troubleshooting/inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS " .

   NO:  Go to Step  3.

   Fig 2: Connecting Scan Tool To Data Link Connector

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

   Replace the combination meter, and then check that the diagnostic trouble code is not reset.

   1. Turn the ignition switch "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 the check result satisfactory? 

   YES:  The procedure is complete.

   NO:  Go to Step  1.

   Fig 3: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.