Inspection Procedure

HINT:

• If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see the undersurface of the seat cushion.
• In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may cause a problem, such as seat rail deformation. Hold the seat only as necessary.

1. CHECK FOR DTC 
   1. Turn the engine switch on (IG).
   2. Clear the DTCs stored in the occupant classification ECU (see DTC CHECK/CLEAR  ).
   3. Clear the DTCs stored in the center airbag sensor (see DTC CHECK/CLEAR  ).
   4. Turn the engine switch off.
   5. Turn the engine switch on (IG).
   6. Check for the DTCs (see DTC CHECK/CLEAR  ).

      OK: 

      DTC B1790 is not output. 

      HINT:

      Codes other than DTC B1790 may be output at this time, but they are not related to this check.

      NG: Go to step 2 

      OK: USE SIMULATION METHOD TO CHECK (See  DIAGNOSIS SYSTEM   ) 

2. CHECK CONNECTION OF CONNECTOR 
   1. Turn the engine switch off.
   2. Disconnect the negative (-) terminal cable from the battery.
   3. Check that the connectors are properly connected to the occupant classification ECU and the center airbag sensor.

      OK: 

      Connectors are properly connected. 

      NG: CONNECT CONNECTORS PROPERLY 

      OK: Go to next step 

3. CHECK CONNECTOR 
   1. Disconnect the connectors from the center airbag sensor and the occupant classification ECU.
   2. Check that the connectors (on the center airbag sensor side and occupant classification ECU side) are not damaged.

      OK: 

      Connectors are not deformed or damaged. 

      NG: REPLACE HARNESS OR CONNECTOR 

      OK: Go to next step 

4. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT 
   1. Connect the negative (-) terminal cable to the battery.
   2. Turn the engine switch on (IG).
   3. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      VOLTAGE SPECIFICATION
      
      

      Tester Connection	Switch Condition	Specified Condition
      e10-11 (FSR+) - Body ground	Engine switch on (IG)	Below 1 V
      e10-12 (FSR-) - Body ground

   4. Turn the engine switch off.
   5. Disconnect the negative (-) terminal cable from the battery.
   6. Using a service wire, connect terminals 16 (FSR+) and 22 (FSR-) of connector B.
      NOTE: Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.
   7. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFICATION
      
      

      Tester Connection	Condition	Specified Condition
      e10-11 (FSR+) - e10-12 (FSR-)	Always	Below 1 Ω

      Fig 1: Checking Occupant Classification System Circuit

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   8. Disconnect the service wire from connector B.
   9. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFICATION
      
      

      Tester Connection	Condition	Specified Condition
      e10-11 (FSR+) - e10-12 (FSR-)	Always	1 MΩ or higher
      e10-11 (FSR+) - Body ground
      e10-12 (FSR-) - Body ground

      NG:  Go to step  10

      OK: Go to next step 

5. CHECK FOR DTC 
   1. Connect the connectors to the occupant classification ECU and the center airbag sensor.
   2. Connect the Techstream to the DLC3.
   3. Connect the negative (-) terminal cable to the battery.
   4. Turn the engine switch on (IG).
   5. Clear the DTCs stored in the occupant classification ECU (see DTC CHECK/CLEAR  ).
   6. Clear the DTCs stored in the center airbag sensor (see DTC CHECK/CLEAR  ).
   7. Turn the engine switch off.
   8. Turn the engine switch on (IG).
   9. Using the Techstream, check for the DTCs of the occupant classification ECU (see DTC CHECK/CLEAR  ).

      OK: 

      DTC B1790 is not output. 

      HINT:

      Codes other than DTC B1790 may be output at this time, but they are not related to this check.

      NG: Go to step 6 

      OK: USE SIMULATION METHOD TO CHECK (See  DIAGNOSIS SYSTEM   ) 

6. REPLACE FRONT SEAT SET (OCCUPANT CLASSIFICATION ECU) 
   1. Connect the Techstream to the DLC3.
   2. Turn the engine switch on (IG).
   3. Using the Techstream, save the ECU data from the ECU which was installed on the vehicle (see REGISTRATION  ).
   4. Turn the engine switch off.
   5. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
   6. Replace the front seat set (occupant classification ECU) (see DISASSEMBLY ).
   7. Connect the negative (-) terminal cable to the battery.
   8. Turn the engine switch on (IG).
   9. Using the Techstream, load the previous ECU data stored in the Techstream into the new ECU (see REGISTRATION  ).
   10. Turn the engine switch off.
   11. Turn the engine switch on (IG).
   12. Clear the DTCs stored in the memory (see DTC CHECK/CLEAR  ).

       HINT:

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

7. CHECK FOR DTC 
   1. Turn the engine switch on (IG).
   2. Clear the DTCs stored in the occupant classification ECU (see DTC CHECK/CLEAR  ).
   3. Clear the DTCs stored in the center airbag sensor (see DTC CHECK/CLEAR  ).
   4. Turn the engine switch off.
   5. Turn the engine switch on (IG).
   6. Using the Techstream, check for the DTCs of the occupant classification ECU (see DTC CHECK/CLEAR  ).

      OK: 

      DTC B1790 is not output. 

      HINT:

      Codes other than DTC B1790 may be output at this time, but they are not related to this check.

      OK:  Go to step  9

      NG: Go to next step 

8. REPLACE CENTER AIRBAG SENSOR ASSEMBLY 
   1. Turn the engine switch off.
   2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
   3. Replace the center airbag sensor (see REMOVAL  ).
9. PERFORM SENSITIVITY CHECK 
   1. Perform the sensitivity check (see INITIALIZATION  ).

      NEXT: END 

10. CHECK FLOOR WIRE 
    1. Turn the engine switch off.
    2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
    3. Disconnect the front seat wire RH connector from the floor wire.
    4. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
    5. Turn the engine switch on (IG).
    6. Measure the voltage according to the value(s) in the table below.

       Standard voltage 

       VOLTAGE SPECIFICATION
       
       

       Tester Connection	Switch Condition	Specified Condition
       Re3-2 (FSR+) - Body ground	Engine switch on (IG)	Below 1 V
       Re3-3 (FSR-) - Body ground

    7. Disconnect the front seat wire RH connector from the floor wire.
    8. Disconnect the negative (-) terminal cable from the battery.
    9. Using service wire, connect terminals 16 (FSR+) and 22 (FSR-) of connector B.
       NOTE: Do not forcibly insert a service wire into the terminals of the connector when connecting the wire.
       Fig 2: Checking Floor Wire

       Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    10. Measure the resistance according to the value(s) in the table below.

        Standard resistance 

        RESISTANCE SPECIFICATION
        
        

        Tester Connection	Condition	Specified Condition
        Re3-2 (FSR+) - Re3-3 (FSR-)	Always	Below 1 Ω

    11. Disconnect the service wire from connector B.
    12. Measure the resistance according to the value(s) in the table below.

        Standard resistance 

        RESISTANCE SPECIFICATION
        
        

        Tester Connection	Condition	Specified Condition
        Re3-2 (FSR+) - Re3-3 (FSR-)	Always	1 MΩ or higher
        Re3-2 (FSR+) - Body ground
        Re3-3 (FSR-) - Body ground

        NG: REPLACE FLOOR WIRE 

        OK: REPLACE FRONT SEAT WIRE RH