Toyota Tacoma (2015-2018) Service Manual: Seat Position Airbag Sensor Circuit Malfunction (B1653/35)

Toyota Tacoma (2015-2018) Service Manual / Supplemental Restraint Systems / Airbag System / Seat Position Airbag Sensor Circuit Malfunction (B1653/35)

DESCRIPTION

The seat position airbag sensor circuit consists of the airbag sensor assembly and the seat position airbag sensor.

DTC B1653/35 is stored when a malfunction is detected in the seat position airbag sensor assembly circuit.

DTC No.	DTC Detection Condition	Trouble Area
B1653/35	The airbag sensor assembly receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the seat position airbag sensor assembly circuit for 2 seconds. Seat position airbag sensor malfunction Airbag sensor assembly malfunction	No. 2 floor wire Seat position airbag sensor Airbag sensor assembly

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 ).

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.

OK:

The connectors are properly connected.

CONNECT CONNECTORS

2.	CHECK CONNECTORS

(a) Disconnect the connector from the airbag sensor assembly.

(b) Disconnect the connector from the seat position airbag sensor.

(c) Check that the connectors (on the airbag sensor assembly side and seat position airbag sensor side) are not damaged (See page ).

OK:

The connectors are not deformed or damaged.

Condition	Proceed to
Normal	A
Abnormal	B

REPLACE HARNESS OR CONNECTOR

3.	CHECK NO. 2 FLOOR WIRE (AIRBAG SENSOR ASSEMBLY - SEAT POSITION AIRBAG SENSOR)

Text in Illustration

*1	Seat Position Airbag Sensor	*2	No. 2 Floor Wire
*3	Airbag Sensor Assembly	*4	Connector C
*5	Connector B	*6	Service Wire
*a	Front view of wire harness connector (to Seat Position Airbag Sensor)	*b	Rear view of wire harness connector (to Airbag Sensor Assembly)

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

(b) Turn the ignition switch to ON.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F20-3 (LSP+) - Body ground	Ignition switch ON	Below 1 V
F20-4 (LSP-) - 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 13 (LSP-) and 14 (LSP+) of connector B.

NOTICE:

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F20-3 (LSP+) - F20-4 (LSP-)	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
F20-3 (LSP+) - F20-4 (LSP-)	Always	1 MΩ or Higher
F20-3 (LSP+) - Body ground	Always	1 MΩ or Higher
F20-4 (LSP-) - Body ground	Always	1 MΩ or Higher

REPLACE NO. 2 FLOOR WIRE

4.	CHECK SEAT POSITION AIRBAG SENSOR

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

(b) Connect the connector to the seat position airbag sensor.

(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. ).

(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 OK: ).

OK:

DTC B1653/35 is not output.

HINT:

DTCs other than B1653/35 may be output at this time, but they are not related to this check.

USE SIMULATION METHOD TO CHECK

5.	REPLACE SEAT POSITION AIRBAG SENSOR

(a) Turn the ignition switch off.

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

HINT:

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

6.	CHECK AIRBAG SENSOR ASSEMBLY

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

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

(d) Turn the ignition switch off.

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

(f) Check for DTCs (See page OK: ).

OK:

DTC B1653/35 is not output.

HINT:

DTCs other than B1653/35 may be output at this time, but they are not related to this check.

END

REPLACE AIRBAG SENSOR ASSEMBLY

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