DTC U1073: Bus Off: Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (MUT-III Sub Assembly)
  • MB991824: V.C.I.
  • MB991827: MUT-III USB Cable
  • MB991910: MUT-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? 

   YES :  Go to Step 2.

   NO :  Repair the CAN bus line (Refer to DIAGNOSIS ). Then go to Step 2.

   Fig 1: Connecting Scan Tool To Data Link Connector

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

   Check again if the DTC is set.

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

   Q: Is DTC U1073 set? 

   YES :  Replace the ABS/TCL-ECU. Then go to Step 3.

   NO :  It can be assumed that this malfunction is intermittent. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .

   Fig 2: Connecting Scan Tool To Data Link Connector

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

   Check again if the DTC is set.

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

   Q: Is DTC U1073 set? 

   YES :  Go to  Step 1.

   NO :  The procedure is complete.

   Fig 3: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.