Toyota Tacoma (2015-2018) Service Manual: Front Airbag Sensor LH Circuit Malfunction (B1615/14)

DESCRIPTION

The front airbag sensor LH consists of parts such as the diagnostic circuit and the frontal detection sensor.

When the airbag sensor assembly receives signals from the frontal deceleration sensor, it determines whether or not the SRS should be activated.

DTC B1615/14 is set when a malfunction is detected in the front airbag sensor LH circuit.

DTC No.	DTC Detecting Condition	Trouble Areas
B1615/14	The airbag sensor assembly receives a line short signal, an open signal, a short to ground signal or a short to B+ signal in the front airbag sensor LH circuit for 2 seconds Front airbag sensor LH malfunction Airbag sensor assembly malfunction	Front airbag sensor LH Airbag sensor assembly Instrument panel wire Engine room main wire

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work (See page ).

PROCEDURE

1.	CHECK CONNECTION OF CONNECTORS

(a) Turn the ignition switch off.

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

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

OK:

The connectors are properly connected.

NG

CONNECT CONNECTORS

OK

2.	CHECK CONNECTOR

(a) Check that the connectors (on the airbag sensor assembly side and front airbag sensor LH side) are not damaged (See page ).

OK:

The connectors are not deformed or damaged.

NG

REPLACE WIRE HARNESS

OK

3.	CHECK FRONT AIRBAG SENSOR LH CIRCUIT (FOR OPEN)

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

(b) Using a service wire, connect A11-2 (+SL) and A11-1 (-SL) of connector E.

NOTICE:

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A21 -30 (+SL) - A21-28 (-SL)	Always	Below 1 Ω

Text in Illustration

*1	Front Airbag Sensor LH
*2	Airbag Sensor Assembly
*3	Service Wire

NG

GO TO STEP 9

OK

4.	CHECK FRONT AIRBAG SENSOR LH CIRCUIT (FOR SHORT)

(a) Disconnect the service wire from connector E.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A21 -30 (+SL) - A21-28 (-SL)	Always	1 MΩ or Higher

Text in Illustration

*1	Front Airbag Sensor LH
*2	Airbag Sensor Assembly

NG

GO TO STEP 10

OK

5.	CHECK FRONT AIRBAG SENSOR LH CIRCUIT (TO B+)

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

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A21 -30 (+SL) - Body ground	Ignition switch ON	Below 1 V
A21-28 (-SL) - Body ground	Ignition switch ON	Below 1 V

Text in Illustration

*1	Front Airbag Sensor LH
*2	Airbag Sensor Assembly

NG

GO TO STEP 11

OK

6.	CHECK FRONT AIRBAG SENSOR LH CIRCUIT (TO GROUND)

(a) Turn the ignition switch off.

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A21 -30 (+SL) - Body ground	Always	1 MΩ or Higher
A21-28 (-SL) - Body ground	Always	1 MΩ or Higher

Text in Illustration

*1	Front Airbag Sensor LH
*2	Airbag Sensor Assembly

NG

GO TO STEP 12

OK

7.	CHECK FRONT AIRBAG SENSOR LH

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

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

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

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

(e) Clear any DTCs stored in the 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 B1615/14 is output.	A
DTC B1610/13 is output.	B
Neither DTC B1610/13 nor B1615/14 is output.	C

B

REPLACE FRONT AIRBAG SENSOR LH

C

USE SIMULATION METHOD TO CHECK

A

8.	REPLACE AIRBAG SENSOR ASSEMBLY

(a) Turn the ignition switch off.

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

(c) Replace the airbag sensor assembly (See page ).

HINT:

Perform the inspection using parts from a normal vehicle when possible.

(d) Connect the connectors to the airbag sensor assembly.

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

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

(g) Clear any DTCs stored in the memory (See page ).

(h) Turn the ignition switch off.

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

(j) Check for DTCs (See page ).

OK:

DTC B1615/14 is not output.

HINT:

DTCs other than B1615/14 may be output at this time, but they are not related to this check.

OK

END

NG

REPLACE FRONT AIRBAG SENSOR LH

9.	CHECK ENGINE ROOM MAIN WIRE (FOR OPEN)

(a) Disconnect the engine room main wire connector from the instrument panel wire. HINT: The service wire has already been inserted into connector E.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
IS1-3 (-SL) - IS1-4 (+SL)	Always	Below 1 Ω

Text in Illustration

*1	Front Airbag Sensor LH
*2	Engine Room Main Wire
*3	Instrument Panel Wire
*4	Airbag Sensor Assembly
*5	Service Wire

OK

REPLACE INSTRUMENT PANEL WIRE

NG

REPLACE ENGINE ROOM MAIN WIRE

10.	CHECK ENGINE ROOM MAIN WIRE (FOR SHORT)

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
IS1-3 (-SL) - IS1-4 (+SL)	Always	1 MΩ or Higher

Text in Illustration

*1	Front Airbag Sensor LH
*2	Engine Room Main Wire
*3	Instrument Panel Wire
*4	Airbag Sensor Assembly

OK

REPLACE INSTRUMENT PANEL WIRE

NG

REPLACE ENGINE ROOM MAIN WIRE

11.	CHECK ENGINE ROOM MAIN WIRE (TO B+)

(a) Turn the ignition switch off.

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

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

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

(e) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
IS1-3 (-SL) - Body ground	Ignition switch ON	Below 1 V
IS1-4 (+SL) - Body ground	Ignition switch ON	Below 1 V

Text in Illustration

*1	Front Airbag Sensor LH
*2	Engine Room Main Wire
*3	Instrument Panel Wire
*4	Airbag Sensor Assembly

OK

REPLACE INSTRUMENT PANEL WIRE

NG

REPLACE ENGINE ROOM MAIN WIRE

12.	CHECK ENGINE ROOM MAIN WIRE (TO GROUND)

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
IS1-3 (-SL) - Body ground	Always	1 MΩ or Higher
IS1-4 (+SL) - Body ground	Always	1 MΩ or Higher

Text in Illustration

*1	Front Airbag Sensor LH
*2	Engine Room Main Wire
*3	Instrument Panel Wire
*4	Airbag Sensor Assembly

OK

REPLACE INSTRUMENT PANEL WIRE

NG

REPLACE ENGINE ROOM MAIN WIRE