DTC B1B8E: Seat Slide Sensor (power supply side) Short 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 seat slide sensor circuit. Measure the voltage at the occupant classification-ECU connector D-35-2. 
   1. Disconnect occupant classification connector-ECU connector D-35-2.
   2. Disconnect seat slide sensor connector D-28.
   3. Turn the ignition switch to the "ON" position.
      CAUTION: Do not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
   4. Measure the voltage between D-35-2 harness side connector terminals 27, 29 and body ground. Voltage should measure 1 volt or less.

   Q: Is the measured voltage within the specified range? 

   • YES:  Go to  Step 5.
   • NO:  Go to Step 4.
     Fig 2: Measuring Voltage Between D-35-2 Harness Side Connector Terminals 27, 29 And Body Ground

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Check the harness wires for short circuit to power supply between the occupant classification-ECU connector D-35-2 (terminal No. 27 and 29) and seat slide sensor connector D-28 (terminal No. 2 and 1). 

   Q: Is the check result normal? 

   • YES:  Go to Step 5.
   • NO:  Repair the harness wires between the occupant classification-ECU connector D-35-2 and seat slide sensor connector D-28. Then go to Step 5.
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 DTC B1B8E 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 6.
   • NO:  The procedure is complete.
6. STEP 6. 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 ).