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 tip over. Holding the seat for a long period of time may cause a problem, such as seat rail deformation. Hold the seat up only for as long as necessary.

CHECK FOR DTC
1. Turn the ignition switch ON.
2. Clear the DTCs (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 B1780 is not output.

HINT:

DTCs other than DTC B1780 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
CHECK CONNECTION OF 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 front occupant classification sensor LH.
OK: The connectors are properly connected.

NG: CONNECT CONNECTOR

OK: GO to Next Step

CHECK FRONT SEAT WIRE RH (TO B+)

Disconnect the connectors from the occupant classification ECU and the front occupant classification sensor LH.
Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
Turn the ignition switch ON.

Measure the voltage of the wire harness side connector.

Standard voltage

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
a1-1 (SGD1) - Body ground	Below 1 V
a1-7 (SIG1) - Body ground	Below 1 V
a1-11 (SVC1) - Body ground	Below 1 V

NG: REPAIR OR REPLACE FRONT SEAT WIRE RH

Fig 1: Checking Front Seat Wire RH (To B+)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: GO to Next Step

CHECK FRONT SEAT WIRE RH (FOR OPEN)

Turn the ignition switch OFF.
Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
Using a service wire, connect terminals a2-1 (SVC1) and a2-3 (SGD1), and connect terminals a2-2 (SIG1) and a2-3 (SGD1) of connector C.
NOTE: Do not forcibly insert a service wire into the terminals of the connector when connecting them.

Measure the resistance of the wire harness side connector.

Standard resistance

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
a1-7 (SIG1) - a1-1 (SGD1)	Below 1 Ω
a1-11 (SVC1) - a1-1 (SGD1)	Below 1 Ω

NG: REPAIR OR REPLACE FRONT SEAT WIRE RH

Fig 2: Checking Front Seat Wire RH (For Open)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

CHECK FRONT SEAT WIRE RH (FOR SHORT)

Disconnect the service wire from connector C.

Measure the resistance of the wire harness side connector.

Standard resistance

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
a1-7 (SIG1) - a1-1 (SGD1)	1 MΩ or higher
a1-11 (SVC1) - a1-1 (SGD1)	1 MΩ or higher
a1-7 (SIG1) - a1-11 (SVC1)	1 MΩ or higher

NG: REPAIR OR REPLACE FRONT SEAT WIRE RH

Fig 3: Checking Front Seat Wire RH (For Short)

OK: GO to Next Step

CHECK FRONT SEAT WIRE RH (TO GROUND)

Measure the resistance of the wire harness side connector.

Standard resistance

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
a1-1 (SGD1) - Body ground	1 MΩ or higher
a1-7 (SIG1) - Body ground	1 MΩ or higher
a1-11 (SVC1) - Body ground	1 MΩ or higher

NG: REPAIR OR REPLACE FRONT SEAT WIRE RH

Fig 4: Checking Front Seat Wire RH (To Ground)

OK: GO to Next Step

CHECK FOR DTC
1. Connect the connectors to the occupant classification ECU and the front occupant classification sensor LH.
2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
3. Turn the ignition switch ON.
4. Clear the DTCs (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 B1780 is not output.

HINT:

DTCs other than DTC B1780 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
REPLACE OCCUPANT CLASSIFICATION ECU
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 occupant classification ECU (see OCCUPANT CLASSIFICATION ECU ).
  HINT:
  
  Perform the inspection using parts from a normal vehicle if possible.
PERFORM ZERO POINT CALIBRATION
1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
2. Connect the intelligent tester (with CAN VIM) to the DLC3.
3. Turn the ignition switch ON.
4. Using the intelligent tester, perform the zero point calibration (see INITIALIZATION ).
OK: COMPLETED is displayed.

NG: GO to step 12

OK: GO to Next Step
PERFORM SENSITIVITY CHECK
1. Using the intelligent tester, perform the sensitivity check (see INITIALIZATION ).
  Standard values:
  
  27 to 33 kg (59.52 to 72.75 lb)
NG: GO to step 12

OK: GO to Next Step
CHECK FOR DTC
1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
2. Turn the ignition switch ON.
3. Clear the DTCs (see DTC CHECK / CLEAR ). HINT:
  First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
4. Turn the ignition switch OFF.
5. Turn the ignition switch ON.
6. Check the DTCs (see DTC CHECK / CLEAR ).
OK: DTC B1780 is not output.

HINT:

Codes other than DTC B1780 may be output at this time, but they are not related to this check.

OK: END

NG: GO to Next Step
REPLACE FRONT SEAT ASSEMBLY RH
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 front seat RH (See REMOVAL ).
PERFORM ZERO POINT CALIBRATION
1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
2. Connect the intelligent tester to the DLC3.
3. Turn the ignition switch ON.
4. Using the intelligent tester, perform the zero point calibration (see INITIALIZATION ).
OK: COMPLETED is displayed.
PERFORM SENSITIVITY CHECK
1. Using the intelligent tester, perform the sensitivity check (see INITIALIZATION ).
  Standard value:
  
  27 to 33 kg (59.52 to 72.75 lb)
NEXT: END