DTC U0154: Occupant Classification-ECU CAN Timeout: 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 (Vehicles with CAN communication system)

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. Refer to "HOW TO CONNECT THE SCAN TOOL (M.U.T.-III)  ."
   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 line. (Refer to DIAGNOSIS ).
      Fig 1: Connecting Scan Tool To Data Link Connector

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Using scan tool MB991958, read the SRS-ECU diagnostic trouble code. 

   Check if DTC is set to the SRS-ECU.

   Q: Is the DTC set? 

   1. YES:  Troubleshoot the SRS. (Refer to DIAGNOSTIC TROUBLE CODE CHART ).
   2. NO:  Go to Step 3.
3. STEP 3. Using scan tool MB991958, read the other system diagnostic trouble code. 

   Check if DTC U0154 is set to the combination meter.

   Q: Is the DTC set? 

   1. YES:  Go to Step 4.
   2. NO:  Go to  Step 5.
4. STEP 4. Recheck for diagnostic trouble code. 

   Check again if the DTC is set to the WCM.

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

   Q: Is the DTC set? 

   1. YES:  Replace the occupant classification-ECU.
   2. NO:  The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).
5. STEP 5. Recheck for diagnostic trouble code. 

   Check again if the DTC is set to the WCM.

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

   Q: Is the DTC set? 

   1. YES:  Replace WCM and register the ID codes (Refer to ID CODES REGISTRATION PROCEDURE ).
   2. NO:  The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).