Toyota 4Runner manuals

Toyota 4Runner: Lost Communication with Front Airbag Sensor LH (B1617/84,B1618/84)

Toyota 4Runner Service Manual / Vehicle Interior / Supplemental Restraint Systems / Airbag System / Lost Communication with Front Airbag Sensor LH (B1617/84,B1618/84)

DESCRIPTION

The front airbag sensor LH circuit consists of the center airbag sensor and front airbag sensor LH.

The front airbag sensor LH detects impacts to the vehicle and sends signals to the center airbag sensor to determine if the airbag should be deployed.

DTC B1617/84 or B1618/84 is stored when a malfunction is detected in the front airbag sensor LH circuit.

DTC Code

DTC Detection Condition

Trouble Area

B1617/84

One of the following conditions is met:

  • The center airbag sensor detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the front airbag sensor LH circuit for 2 seconds.
  • A front airbag sensor LH malfunction.
  • A center airbag sensor malfunction.
  • Instrument panel wire
  • Engine room main wire
  • Front airbag sensor LH
  • Center airbag sensor assembly

B1618/84

One of the following conditions is met:

  • The center airbag sensor detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the front airbag sensor LH circuit for 2 seconds.
  • A front airbag sensor LH malfunction.
  • A center airbag sensor malfunction.
  • Instrument panel wire
  • Engine room main wire
  • Front airbag sensor LH
  • Center airbag sensor assembly

WIRING DIAGRAM


CAUTION / NOTICE / HINT

NOTICE:

When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected (See page ).


PROCEDURE

1.

CHECK CONNECTION OF CONNECTORS

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Check that the connectors are properly connected to the center airbag sensor and front airbag sensor LH.

OK:

The connectors are properly connected.


NG

CONNECT CONNECTORS PROPERLY


OK

2.

CHECK CONNECTORS

(a) Disconnect the connectors from the center airbag sensor and front airbag sensor LH.

(b) Check that the connectors (on the center airbag sensor side and front airbag sensor LH side) are not damaged.

OK:

The connectors are not deformed or damaged.

Text in Illustration

*1

Front Airbag Sensor LH

*2

Center Airbag Sensor



NG

REPLACE HARNESS AND CONNECTOR


OK

3.

CHECK FRONT AIRBAG SENSOR LH CIRCUIT

(a) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

Text in Illustration

*1

Front Airbag Sensor LH

*2

Center Airbag Sensor

*3

Connector E

*4

Connector B

*5

Service Wire

-

-

*a

Front view of wire harness connector

(to Front Airbag Sensor LH)

*b

Rear view of wire harness connector

(to Center Airbag Sensor)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A13-2 (+SL) - Body ground

Ignition switch ON

Below 1 V

A13-1 (-SL) - Body ground

Ignition switch ON

Below 1 V

(c) Turn the ignition switch off.

(d) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(e) Using a service wire, connect terminals 30 (+SL) and 28 (-SL) of connector B.

NOTICE:

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A13-2 (+SL) - A13-1 (-SL)

Always

Below 1 Ω

(g) Disconnect the service wire from connector B.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A13-2 (+SL) - A13-1 (-SL)

Always

1 MΩ or higher

A13-2 (+SL) - Body ground

Always

1 MΩ or higher

A13-1 (-SL) - Body ground

Always

1 MΩ or higher


NG

GO TO STEP 5


OK

4.

CHECK FRONT AIRBAG SENSOR LH

(a) Connect the connectors to the center airbag sensor.


(b) Interchange the front airbag sensor LH with RH and connect the connectors to them.

(c) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

(d) Turn the ignition switch to ON, and wait for at least 60 seconds.

(e) Clear the DTCs stored in memory (See page
).

(f) Turn the ignition switch off.

(g) Turn the ignition switch to ON, and wait for at least 60 seconds.

(h) Check for DTCs (See page ).


Result

Result

Proceed to

DTC B1617 or B1618 is output

A

DTC B1612 or B1613 is output

B

DTC B1612, B1613, B1617 and B1618 are not output

C

HINT:

Codes other than DTC B1612, B1613, B1617 and B1618 may be output at this time, but they are not related to this check.

Text in Illustration

*1

Front Airbag Sensor RH

*2

Center Airbag Sensor


C

USE SIMULATION METHOD TO CHECK


A

REPLACE CENTER AIRBAG SENSOR ASSEMBLY


B

REPLACE FRONT AIRBAG SENSOR LH

5.

CHECK INSTRUMENT PANEL WIRE (CENTER AIRBAG SENSOR - ENGINE ROOM MAIN WIRE)

(a) Disconnect the instrument panel wire connector from the engine room main wire.

Text in Illustration

*1

Front Airbag Sensor LH

*2

Center Airbag Sensor

*3

Engine Room Main Wire

*4

Instrument Panel Wire

*5

Connector C

*6

Connector B

*7

Service Wire

-

-

*a

Front view of wire harness connector

(to Engine Room Main Wire)

*b

Rear view of wire harness connector

(to Center Airbag Sensor)

(b) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

FA4-2 (+SL) - Body ground

Ignition switch ON

Below 1 V

FA4-1 (-SL) - Body ground

Ignition switch ON

Below 1 V

(d) Turn the ignition switch off.

(e) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(f) Using a service wire, connect terminals 30 (+SL) and 28 (-SL) of connector B.

NOTICE:

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

FA4-2 (+SL) - FA4-1 (-SL)

Always

Below 1 Ω

(h) Disconnect the service wire from connector B.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

FA4-2 (+SL) - FA4-1 (-SL)

Always

1 MΩ or higher

FA4-2 (+SL) - Body ground

Always

1 MΩ or higher

FA4-1 (-SL) - Body ground

Always

1 MΩ or higher


OK

REPLACE ENGINE ROOM MAIN WIRE


NG

REPLACE INSTRUMENT PANEL WIRE

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