Toyota RAV4 Service Manual: Center airbag sensor assembly communication circuit malfunction

Description
The center airbag sensor communication circuit consists of the occupant
classification ecu and the
center airbag sensor.
Dtc b1790 is recorded when a malfunction is detected in the center airbag sensor
communication circuit.

Wiring diagram

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
- Turn the ignition switch on.
- Clear the dtcs (see page rs-249).
Hint:
First clear dtcs stored in the occupant classification
ecu and then in the center airbag sensor.
- Turn the ignition switch off.
- Turn the ignition switch on.
- Check the dtcs (see page rs-249).
Ok:
dtc b1790 is not output.
Hint:
Dtcs other than dtc b1790 may be output at this time,
but they are not related to this check.

- Check connection of connector
- Turn the ignition switch off.
- Disconnect the cable from the negative (-) battery
terminal, and wait for at least 90 seconds.
- Check that the connectors are properly connected to the
occupant classification ecu and the center airbag
sensor.
Ok:
the connectors are properly connected.

- Check floor wire (to b+)

- Disconnect the connectors from the occupant
classification ecu and the center airbag sensor.
- 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 

- Check floor wire (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 l6-12 (fsp+) *1
and l6-13 (fsp-) *1 or l7-16 (fsp+) *2 and l7-24
(fsp-) *2 of connector b.
Notice:
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
Hint:
*1: W/o curtain shield airbag
*2: W/ curtain shield airbag

- Check floor wire (for short)

- Disconnect the service wire from connector b.
- Measure the resistance of the wire harness side
connector.
Standard resistance 

- Check floor wire (to ground)

- Measure the resistance of the wire harness side
connector.
Standard resistance 

- Check for dtc
- Connect the connectors to the occupant classification
ecu and the center airbag sensor.
- Connect the cable to the negative (-) battery terminal,
and wait for at least 2 seconds.
- Turn the ignition switch on.
- Clear the dtcs (see page rs-249).
Hint
First clear dtcs stored in the occupant classification
ecu and then in the center airbag sensor.
- Turn the ignition switch off.
- Turn the ignition switch on.
- Check the dtcs (see page rs-249).
Ok:
dtc b1790 is not output.
Hint:
Dtcs other than dtc b1790 may be output at this time,
but they are not related to this check.

- Replace occupant classification ecu
- Turn the ignition switch off.
- Disconnect the cable from the negative (-) battery
terminal, and wait for at least 90 seconds.
- Replace the occupant classification ecu (see page rs-
392).
Hint:
Perform the inspection using parts from a normal vehicle
if possible.
- Perform zero point calibration
- Connect the cable to the negative (-) battery terminal,
and wait for at least 2 seconds.
- Connect the intelligent tester (with can vim) to the
dlc3.
- Turn the ignition switch on.
- Using the intelligent tester, perform the zero point
calibration (see page rs-241).
Ok:
completed is displayed.
- Perform sensitivity check
- Using the intelligent tester, perform the sensitivity check
(see page rs-241).
Standard value:
27 to 33 kg (59.52 To 72.75 Lb)
- Check for dtc
- Turn the ignition switch on.
- Clear the dtcs (see page rs-249).
Hint:
First clear dtcs stored in the occupant classification
ecu and then in the center airbag sensor.
- Turn the ignition switch off.
- Turn the ignition switch on.
- Check the dtcs (see page rs-249).
Ok:
dtc b1790 is not output.
Hint:
Dtcs other than dtc b1790 may be output at this time,
but they are not related to this check.

End
Description
Dtc b1788 is output when the occupant classification ecu receives a collision
detection signal sent by
the rear occupant classification sensor rh when an accident occurs.
Dtc b1 ...
Description
The occupant classification sensor power supply circuit consists of the
occupant classification ecu and
the occupant classification sensors.
Dtc b1793 is recorded when a malfunc ...
Other materials:
Transmission fluid temperature sensor "A" circuit
Description
The automatic transmission fluid (atf) temperature sensor converts the atf
temperature into a
resistance value which is input into the ecm.
The ecm applies a voltage to the temperature sensor through ecm terminal tho1.
The sensor resistance changes with the atf temperature. ...
Lost communication with front satellite sensor bus rh
Description
The front airbag sensor rh consists of the diagnostic circuit and the frontal
deceleration sensor.
If the center airbag sensor receives signals from the frontal deceleration
sensor, it determines whether or
not the srs should be activated.
Dtc b1602/83, b1603/83, b1612/83 ...
Head restraints
Head restraints are provided for all seats.
Front seats
Up
Pull the head restraints up.
Down
Push the head restraint down while
pressing the lock release button.
Rear seats
Up
Pull the head restraints up.
Down
Push the head restraint down while
pressing the lock rel ...