Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see the under surface 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.

CHECK DTC
1. Turn the ignition switch to the ON position.
2. Clear the DTCs stored in the occupant classification ECU (See DTC CHECK / CLEAR ).
3. Clear the DTCs stored in the center airbag sensor assembly (See DTC CHECK / CLEAR ).
4. Turn the ignition switch to the ON position.
5. Turn the ignition switch to the LOCK position.
6. Turn the ignition switch to the ON position.
7. 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: USE SIMULATION METHOD TO CHECK

NG: Go to next step
CHECK CONNECTION OF CONNECTORS
1. Turn the ignition switch to the LOCK position.
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 front occupant classification sensor LH.
  OK:
  
  The connectors are properly connected.
NG: CONNECT CONNECTOR PROPERLY, THEN GO TO STEP 1

OK: Go to next step

CHECK FRONT SEAT WIRE RH (SHORT TO B+)

Disconnect the connectors from the occupant classification ECU and the front occupant classification sensor LH.
Connect the negative (-.) terminal cable to the battery.
Turn the ignition switch to the ON position.

Measure the voltage according to the value(s) in the table below.

Standard voltage

STANDARD VOLTAGE

Tester Connection	Condition	Specified Condition
O4-1 (SGD1) - Body ground	Ignition switch ON	Below 1 V
O4-7 (SIG1) - Body ground	Ignition switch ON	Below 1 V
O4-11 (SVC1) - Body ground	Ignition switch ON	Below 1 V

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

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE FRONT SEAT WIRE RH

OK: Go to next step

CHECK FRONT SEAT WIRE RH (OPEN)

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

Measure the resistance according to the value(s) in the table below.

Standard resistance

STANDARD RESISTANCE

Tester Connection	Condition	Specified Condition
O4-7 (SIG1) - O4-1 (SGD1)	Always	Below 1 Ω
O4-11 (SVC1) - O4-1 (SGD1)	Always	Below 1 Ω

Fig 2: Checking Front Seat Wire RH (Open)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE FRONT SEAT WIRE RH

OK: Go to next step

CHECK FRONT SEAT WIRE RH (SHORT)

Disconnect the service wire from connector C.

Measure the resistance according to the value(s) in the table below.

Standard resistance

STANDARD RESISTANCE

Tester Connection	Condition	Specified Condition
O4-7 (SIG1) - O4-1 (SGD1)	Always	1 MΩ or higher
O4-11 (SVC1) - O4-1 (SGD1)	Always	1 MΩ or higher
O4-7 (SIG1) - O4-11 (SVC1)	Always	1 MΩ or higher

Fig 3: Checking Front Seat Wire RH (Short)

NG: REPAIR OR REPLACE FRONT SEAT WIRE RH

OK: Go to next step

CHECK FRONT SEAT WIRE RH (SHORT TO GROUND)

Measure the resistance according to the value(s) in the table below.

Standard resistance

STANDARD RESISTANCE

Tester Connection	Condition	Specified Condition
O4-1 (SGD1) - Body ground	Always	1 MΩ or higher
O4-7 (SIG1) - Body ground	Always	1 MΩ or higher
O4-11 (SVC1) - Body ground	Always	1 MΩ or higher

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

NG: REPAIR OR REPLACE FRONT SEAT WIRE RH

OK: Go to next step

CHECK DTC
1. Connect the connectors to the occupant classification ECU and the front occupant classification sensor LH.
2. Connect the negative (-) terminal cable to the battery.
3. Turn the ignition switch to the ON position.
4. Clear the DTCs stored in the occupant classification ECU (See DTC CHECK / CLEAR ).
5. Clear the DTCs stored in the center airbag sensor assembly (See DTC CHECK / CLEAR ).
6. Turn the ignition switch to the LOCK position.
7. Turn the ignition switch to the ON position.
8. 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: USE SIMULATION METHOD TO CHECK

NG: Go to next step
REPLACE OCCUPANT CLASSIFICATION ECU
1. Turn the ignition switch to the LOCK position.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Replace the occupant classification ECU (See REMOVAL ).
  HINT:
  
  Perform the inspection using parts from a normal vehicle if possible.
PERFORM ZERO POINT CALIBRATION
1. Connect the negative (-) terminal cable to the battery.
2. Connect the intelligent tester to the DLC3.
3. Turn the ignition switch to the ON position.
4. Using the intelligent tester, perform "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 "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 DTC
1. Turn the ignition switch to the ON position.
2. Clear the DTCs stored in the occupant classification ECU (See DTC CHECK / CLEAR ).
3. Clear the DTCs stored in the center airbag sensor assembly (See DTC CHECK / CLEAR ).
4. Turn the ignition switch to the LOCK position.
5. Turn the ignition switch to the ON position.
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 to the LOCK position.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Replace the front seat assembly RH (See REMOVAL ).
PERFORM ZERO POINT CALIBRATION
1. Connect the negative (-) terminal cable to the battery.
2. Connect the intelligent tester to the DLC3.
3. Turn the ignition switch to the ON position.
4. Using the intelligent tester, perform "zero point calibration" (See INITIALIZATION ).
  OK:
  
  "COMPLETED" is displayed.
PERFORM SENSITIVITY CHECK
1. Using the intelligent tester, perform "sensitivity check" (See INITIALIZATION ).
  Standard values:
  
  27 to 33 kg (59.52 to 72.75 lb)
NEXT: END