Toyota RAV4 manuals

Toyota Sienna Service Manual: Front Occupant Classification Sensor LH Circuit Malfunction

DTC B1780 Front Occupant Classification Sensor LH Circuit Malfunction

DESCRIPTION

The front occupant classification sensor LH circuit consists of the occupant classification ECU and the front occupant classification sensor LH.

DTC B1780 is recorded when a malfunction is detected in the front occupant classification sensor LH circuit.

DESCRIPTION

WIRING DIAGRAM

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

1 CHECK DTC

  1. Turn the ignition switch to the ON position.
  2. Clear the DTCs stored in the memory.

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

  3.  Turn the ignition switch to the LOCK position.
  4.  Turn the ignition switch to the ON position.
  5.  Check the DTCs.

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.

2 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.

3 CHECK FRONT SEAT WIRE RH (SHORT TO B+)

CHECK FRONT SEAT WIRE RH (SHORT TO B+)

  1. Disconnect the connectors from 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.  Measure the voltage according to the value(s) in the table below.

Standard voltage

Standard voltage

4 CHECK FRONT SEAT WIRE RH (OPEN)

CHECK FRONT SEAT WIRE RH (OPEN)

  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.  Using a service wire, connect O5-1 (SVC1) and O5-3 (SGD1), and connect O5-2 (SIG1) and O5-3 (SGD1) of connector "C".

    NOTICE: Do not forcibly insert a service wire into the terminals of the connector when connecting.

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

Standard resistance

Standard resistance

5 CHECK FRONT SEAT WIRE RH (SHORT)

CHECK FRONT SEAT WIRE RH (SHORT)

  1. Disconnect the service wire from connector "C".
  2. Measure the resistance according to the value(s) in the table below.

Standard resistance

Standard resistance

6 CHECK FRONT SEAT WIRE RH (SHORT TO GROUND)

CHECK FRONT SEAT WIRE RH (SHORT TO GROUND)

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

Standard resistance

Standard resistance

7 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 memory.

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

  5.  Turn the ignition switch to the LOCK position.
  6.  Turn the ignition switch to the ON position.
  7.  Check the DTCs.

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.

8 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.

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

9 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".

OK: "COMPLETED" is displayed.

10 PERFORM SENSITIVITY CHECK

  1. Using the intelligent tester, perform "Sensitivity check".

Standard value: 27 to 33 kg (59.52 to 72.75 lb)

11 CHECK DTC

  1. Turn the ignition switch to the ON position.
  2. Clear the DTCs stored in the memory.

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

  3.  Turn the ignition switch to the LOCK position.
  4.  Turn the ignition switch to the ON position.
  5.  Check the DTCs.

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.

12 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.

13 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".

OK: "COMPLETED" is displayed.

14 PERFORM SENSITIVITY CHECK

  1. Using the intelligent tester, perform "Sensitivity check".

Standard value: 27 to 33 kg (59.52 to 72.75 lb)

END

Passenger Side Buckle Switch Circuit Malfunction
DTC B1771 Passenger Side Buckle Switch Circuit Malfunction DESCRIPTION The passenger side buckle switch circuit consists of the occupant classification ECU and the front seat inner belt assembly ...

Front Occupant Classification Sensor RH Circuit Malfunction
DTC B1781 Front Occupant Classification Sensor RH Circuit Malfunction DESCRIPTION The front occupant classification sensor RH circuit consists of the occupant classification ECU and the front oc ...

Other materials:

Engine immobilizer system
The vehicle’s keys have built-in transponder chips that prevent the engine from starting if a key has not been previously registered in the vehicle’s on-board computer. Never leave the keys inside the vehicle when you leave the vehicle. This system is designed to help prevent vehicle the ...

Brake fluid
Checking fluid level The brake fluid level should be between the “MAX” and “MIN” lines on the tank. “MAX” line “MIN” line Adding fluid Lift the cover off. Make sure to check the fluid type and prepare the necessary item. Brake fluid can absorb moisture from t ...

Transmitter ID1 Operation Stop
DESCRIPTION The tire pressure warning valve and transmitters that are installed in the tire and wheel assemblies measure the air pressures of the tires. The measured values are transmitted to the tire pressure warning antenna and receiver on the body as radio waves and then sent to the ti ...

© 2011-2025 Copyright www.tsienna.net