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Home >> Toyota >> 2008 >> FJ Cruiser RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 69 (Supplemental Restraint System) >> Occupant Classification System >> B1772: Seat Position Sensor Circuit Malfunction >> Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2007 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

  1. CHECK FOR DTC 
    1. Turn the ignition switch ON.
    2. Clear the DTCs stored in the memory (see DTC CHECK/CLEAR  ).

      HINT:

      First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

    3. Turn the ignition switch OFF.
    4. Turn the ignition switch ON.
    5. Check the DTCs (see DTC CHECK/CLEAR  ).

      OK: DTC B1772 is not output. 

      HINT:

      DTCs other than B1772 may be output at this time, but they are not related to this check.

    OK: USE SIMULATION METHOD TO CHECK 

    NG: GO TO NEXT STEP 

  2. CHECK CONNECTOR 
    1. Turn the ignition switch OFF.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Check that the connectors are properly connected to the occupant classification ECU and the seat position sensor.

      OK: The connectors are properly connected. 

    4. Disconnect the connectors from the occupant classification ECU and the seat position sensor.
    5. Check that the terminals of the connectors are not damaged.

      OK: The terminals are not deformed or damaged. 

      HINT:

      If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  3. CHECK NO. 1 SEAT WIRE (TO B+) 
    1. Disconnect the connectors from the occupant classification ECU and the seat position sensor.
    2. Connect the cable to the negative (-) battery terminal.
    3. Turn the ignition switch ON.
    4. Measure the voltage of the wire harness side connector.

      Standard voltage 

      NO. 1 SEAT WIRE (TO B+)

      Tester Connection Specified Condition
      O6-4 (SP) - Body ground Below 1 V
      O6-3 (GSP) - Body ground Below 1 V
      Fig 1: Checking No. 1 Seat Wire (To B+)
      G04438234Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE NO. 1 SEAT WIRE 

    OK: GO TO NEXT STEP 

  4. CHECK NO. 1 SEAT WIRE (FOR OPEN) 
    1. Turn the ignition switch OFF.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Using a service wire, connect terminals S23-2 (VS) and S23-1 (GSP) of connector C.
      NOTE: Do not forcibly insert the service wire into the terminals of the connector when connecting.
    4. Measure the resistance of the wire harness side connector.

      Standard resistance 

      NO. 1 SEAT WIRE (FOR OPEN)

      Tester Connection Specified Condition
      O6-4 (SP) - O6-3 (GSP) Below 1 Ω
      Fig 2: Checking No. 1 Seat Wire (For Open)
      G04438235Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE NO. 1 SEAT WIRE 

    OK: GO TO NEXT STEP 

  5. CHECK NO. 1 SEAT WIRE (TO GROUND) 
    1. Disconnect the service wire from connector C.
    2. Measure the resistance of the wire harness side connector.

      Standard resistance 

      NO. 1 SEAT WIRE (TO GROUND)

      Tester Connection Specified Condition
      O6-4 (SP) - Body ground 1 MΩ or higher
      O6-3 (GSP) - Body ground 1 MΩ or higher
      Fig 3: Checking No. 1 Seat Wire (To Ground)
      G04438236Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE NO. 1 SEAT WIRE 

    OK: GO TO NEXT STEP 

  6. CHECK NO. 1 SEAT WIRE (FOR SHORT) 
    1. Measure the resistance of the wire harness side connector.

      Standard resistance 

      NO. 1 SEAT WIRE (FOR SHORT)

      Tester Connection Specified Condition
      O6-4 (SP) - O6-3 (GSP) 1 MΩ or higher
      Fig 4: Checking No. 1 Seat Wire (For Short)
      G04438237Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE NO. 1 SEAT WIRE 

    OK: GO TO NEXT STEP 

  7. CHECK FOR DTC 
    1. Connect the connectors to the occupant classification ECU and the seat position sensor.
    2. Connect the cable to the negative (-) battery terminal.
    3. Turn the ignition switch ON.
    4. Clear the DTCs stored in the memory (see DTC CHECK/CLEAR  ).

      HINT:

      First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

    5. Turn the ignition switch OFF.
    6. Turn the ignition switch ON.
    7. Check the DTCs (see DTC CHECK/CLEAR  ).

      OK: DTC B1772 is not output. 

      HINT:

      DTCs other than B1772 may be output at this time, but they are not related to this check.

    OK: USE SIMULATION METHOD TO CHECK 

    NG: GO TO NEXT STEP 

  8. REPLACE SEAT POSITION SENSOR 
    1. Turn the ignition switch OFF.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Replace the seat position sensor (see INITIALIZATION  ).

      HINT:

      • Perform the inspection using parts from a normal vehicle if possible.
      • The seat position sensor is installed on the driver side.
    4. Connect the cable to the negative (-) battery terminal.
    5. Turn the ignition switch ON.
    6. Clear the DTCs stored in the memory (see DTC CHECK/CLEAR  ).

      HINT:

      First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

    7. Turn the ignition switch OFF.
    8. Turn the ignition switch ON.
    9. Check the DTCs (see DTC CHECK/CLEAR  ).

      OK: DTC B1772 is not output. 

      HINT:

      DTCs other than B1772 may be output at this time, but they are not related to this check.

    OK: END 

    NG: GO TO NEXT STEP 

  9. REPLACE OCCUPANT CLASSIFICATION ECU 
    1. Connect the intelligent tester (with CAN VIM) to the DLC3.
    2. Turn the ignition switch ON.
    3. Store the occupant classification ECU data into the intelligent tester (see REGISTRATION  ).

      HINT:

      If the ECU data cannot be stored in the intelligent tester, replace the front seat cushion (with occupant classification ECU and occupant classification sensor).

    4. Turn the ignition switch OFF.
    5. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    6. Replace the occupant classification ECU (see REMOVAL  ).
    7. Connect the cable to the negative (-) battery terminal.
    8. Turn the ignition switch ON.
    9. Load the data from the previous ECU stored in the tester into the newly installed ECU (see REGISTRATION  ).
    10. Turn the ignition switch OFF.
    11. Turn the ignition switch ON.
    12. Clear the DTCs stored in the memory (see DTC CHECK/CLEAR  ).

      HINT:

      If DTCs are not cleared at this time, past DTCs will remain.

  10. PERFORM SENSITIVITY CHECK 
    1. Perform the sensitivity check (see INITIALIZATION  ).

    END