DTC B1B8D: Driver Seat Slide Sensor Open Circuit: 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  ."
   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 ).
     Fig 1: Connecting Special Tool MB991910 To Data Link Connector

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

   Check again if the DTC is stored.

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

   Q: Is the DTC stored? 

   • YES:  Go to Step 3.
   • NO:  There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
3. STEP 3. Check the harness for open circuit between occupant classification-ECU connector D-35-2 (terminal No. 27 and 29) and the seat slide sensor connector D-28 (terminal No. 2 and 1). 
   1. Disconnect occupant classification-ECU connector D-35-2 and seat slide sensor connector D-28.
      CAUTION: Do not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
   2. Check for continuity between the following terminals. It should be less than 2 ohms.
      • Occupant classification-ECU connector D-35-2 (terminal No. 27) and the seat slide sensor connector D-28 (terminal No. 2)
      • Occupant classification-ECU connector D-35-2 (terminal No. 29) and the seat slide sensor connector D-28 (terminal No. 1)

   Q: Does continuity exist? 

   • YES:  Go to Step 4.
   • NO:  Repair the harness wires between occupant classification-ECU connector D-35-2 and seat slide sensor connector D-28.
     Fig 2: Checking Continuity Between Occupant Classification-ECU Connector D-35-2 (Terminal 27) And Seat Slide Sensor Connector D-28 (Terminal 2)

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Recheck for diagnostic trouble code. 

   Check again if the DTC is stored in the occupant classification-ECU.

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

   Q: Is DTC B1B8D stored? 

   • YES:  Replace the front seat cushion frame (LH) (Refer to DISASSEMBLY AND ASSEMBLY ) < Except RALLIART > or replace the slide adjuster (LH) (Refer to DISASSEMBLY AND ASSEMBLY ) < RALLIART >. Then go to Step 5.
   • NO:  There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
5. STEP 5. Recheck for diagnostic trouble code. 

   Check again if the DTC is stored in the occupant classification-ECU.

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

   Q: Is the DTC stored? 

   • YES:  Replace the front seat cushion frame (RH) (Refer to DISASSEMBLY AND ASSEMBLY ) < Except RALLIART > or replace the slide adjuster (RH) (Refer to DISASSEMBLY AND ASSEMBLY ) < RALLIART >.
   • NO:  There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).