Toyota RAV4 (XA40) 2013-2018 Service Manual: Lost communication with front satellite sensor bus lh

Description

The front airbag sensor lh 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 b1607/84, b1608/84, b1617/84 or b1618/84 is recorded when a malfunction is detected in the front airbag sensor lh circuit.

Wiring diagram

Inspection procedure

1. Check connection of connector

1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) terminal, and wait for at least 90 seconds.
3. Check that the connectors are properly connected to the center airbag sensor and the front airbag sensor lh.

Ok: the connectors are properly connected.

2. Check front airbag sensor lh circuit (open)

1. Disconnect the connectors from the center airbag sensor and the front airbag sensor lh.
2. Using a service wire, connect a15-2 (+sl) and a15-1 (- sl) of connector e.

Notice:

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

3. Measure the resistance of the wire harness side connector.

Standard resistance

3. Check front airbag sensor lh circuit (short)

1. Disconnect the service wire from connector e.
2. Measure the resistance of the wire harness side connector.

Standard resistance

4. Check front airbag sensor lh circuit (to b+)

1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
2. Turn the ignition switch on.
3. Measure the voltage of the wire harness side connectors.

Standard voltage

5. Check front airbag sensor lh circuit (to ground)

1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Measure the resistance of the wire harness side connector.

Standard resistance

6. Check front airbag sensor lh

1. Connect the connectors to the center airbag sensor.
2. Interchange the front airbag sensor rh and lh, and connect the connectors to them.
3. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
4. Turn the ignition switch on, and wait for at least 60 seconds.
5. Clear the dtcs (see page rs-49).
6. Turn the ignition switch off
7. Turn the ignition switch on, and wait for at least 60 seconds.
8. Check the dtcs (see page rs-49).

Result

Hint:

Dtcs other than b1602/83, b1603/83, b1612/83, b1613/83, b1607/84, b1608/84, b1617/84 and b1618/ 84 may be output at this time, but they are not related to this check.

Use simulation method to check

7. Check engine room main wire (open)

1. Disconnect the service wire from connector e.
2. Disconnect the engine room main wire connector from the instrument panel wire.
3. Using a service wire, connect ae5-1 (+sl) and ae5-2 (- sl) of connector d.

Notice:

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

4. Measure the resistance of the wire harness side connector.

Standard resistance

Repair or replace instrument panel wire

8. Check engine room main wire (short)

1. Disconnect the engine room main wire connector from the instrument panel wire.
2. Measure the resistance of the wire harness side connector.

Standard resistance

Repair or replace instrument panel wire

9. Check engine room main wire (to b+)

1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Disconnect the engine room main wire connector from the instrument panel wire.
4. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
5. Turn the ignition switch on.
6. Measure the voltage of the wire harness side connector

Standard voltage

Repair or replace instrument panel wire

10. Check engine room main wire (to ground)

1. Disconnect the engine room main wire connector from the instrument panel wire.
2. Measure the resistance of the wire harness side connector.

 Standard resistance

Repair or replace instrument panel wire