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

      OK: 

      DTC B1772 is not output. 

      HINT:

      Codes other than B1772 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 ignition switch to OFF.
   2. Disconnect the negative (-) terminal cable from the battery, 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: 

      Connectors are properly connected. 

   NG : CONNECT CONNECTORS PROPERLY 

   OK: Go to next step 

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

      OK: 

      Connectors are not deformed or damaged. 

      HINT:

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

   NG : REPLACE FRONT SEAT WIRE RH 

   OK: Go to next step 

4. CHECK FRONT SEAT WIRE RH 
   1. Connect the negative (-) terminal cable to the battery.
   2. Turn the ignition switch to ON.
   3. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED VOLTAGE CONDITION CHART
      
      

      Tester Connection	Switch Condition	Specified Condition
      M2-4 (SP) - Body ground	Ignition switch ON	Below 1 V
      M2-3 (GSP) - Body ground

   4. Turn the ignition switch to OFF.
   5. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
   6. Using a service wire, connect terminals 2 (SP) and 1 (GSP) of connector C.
      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 

      TESTER CONNECTION SPECIFIED RESISTANCE CONDITION CHART
      
      

      Tester Connection	Condition	Specified Condition
      M2-4 (SP) - M2-3 (GSP)	Always	Below 1 Ω

   8. Disconnect the service wire from connector C.
   9. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED RESISTANCE CONDITION CHART
      
      

      Tester Connection	Condition	Specified Condition
      M2-4 (SP) - Body ground	Always	1 MΩ or higher
      M2-3 (GSP) - Body ground
      M2-4 (SP) - M2-3 (GSP)

      Fig 1: Checking Front Seat Wire RH

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG : REPLACE FRONT SEAT WIRE RH 

   OK: Go to next step 

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

      OK: 

      DTC B1772 is not output. 

      HINT:

      Codes other than DTC B1772 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 SEAT POSITION SENSOR 
   1. Turn the ignition switch to OFF.
   2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
   3. Replace the seat position sensor (see REMOVAL  ).

      HINT:

      Perform the inspection using parts from a normal vehicle if possible.

   4. Connect the negative (-) terminal cable to the battery.
7. CHECK FOR DTC 
   1. Turn the ignition switch to ON.
   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 ignition switch to OFF.
   5. Turn the ignition switch to ON.
   6. Check for the DTCs (see DTC CHECK / CLEAR  ).

      OK: 

      DTC B1772 is not output. 

      HINT:

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

   NG: Go to step 8 

   OK : END 

8. PERFORM REGISTRATION BEFORE ECU EXCHANGE 
   1. Connect an intelligent tester or Techstream to the DLC3.
   2. Turn the ignition switch to ON.
   3. Using the intelligent tester or Techstream, save the ECU data from the ECU which was installed on the vehicle (see REGISTRATION  ).
9. REPLACE OCCUPANT CLASSIFICATION ECU 
   1. Turn the ignition switch to OFF.
   2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
   3. Replace the occupant classification ECU (see REMOVAL  ).
   4. Connect the negative (-) terminal cable to the battery.
10. PERFORM REGISTRATION AFTER ECU EXCHANGE 
    1. Turn the ignition switch to ON.
    2. Using an intelligent tester or Techstream, load the previous ECU data stored in the tester into the new ECU (see REGISTRATION  ).
11. PERFORM ZERO POINT CALIBRATION 
    1. Using an intelligent tester or Techstream, perform zero point calibration (see INITIALIZATION  ).
12. CHECK FOR DTC 

    HINT:

    Check that the zero point calibration is completed normally. If one of the following conditions is met, DTC B1797 will be output (refer to INITIALIZATION  ).

    • Zero point calibration is performed when the conditions for the calibration are not satisfied.
    • Zero point calibration has failed.
    1. Clear the DTCs stored in the occupant classification ECU (see DTC CHECK / CLEAR  ).
    2. Clear the DTCs stored in the center airbag sensor (see DTC CHECK / CLEAR  ).
    3. Turn the ignition switch to OFF.
    4. Turn the ignition switch to ON.
    5. Check for the DTCs (see DTC CHECK / CLEAR  ).

       OK: 

       DTC B1797 is not output. 

    NG:  Go TO DTC B1797 

    OK: Go to next step 

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

    NEXT : END