Toyota Tacoma (2015-2018) Service Manual: Short in Side Squib LH Circuit (B1825/56-B1828/56)

DESCRIPTION

The side squib LH circuit consists of the airbag sensor assembly and the front seat airbag assembly LH.

This circuit signals the SRS to deploy when airbag deployment conditions are met.

These DTCs are set when a malfunction is detected in the side squib LH circuit.

DTC No.	DTC Detecting Conditions	Trouble Areas
B1825/56	The airbag sensor assembly receives a line short circuit signal in the side squib LH circuit for 2 seconds Side squib LH malfunction Airbag sensor assembly malfunction	No. 2 floor wire Front seat airbag assembly LH (Side squib LH) Airbag sensor assembly
B1826/56	The airbag sensor assembly receives an open circuit signal in the side squib LH circuit for 2 seconds Side squib LH malfunction Airbag sensor assembly malfunction	No. 2 floor wire Front seat airbag assembly LH (Side squib LH) Airbag sensor assembly
B1827/56	The airbag sensor assembly receives a short circuit to ground signal in the side squib LH circuit for 0.5 seconds Side squib LH malfunction Airbag sensor assembly malfunction	No. 2 floor wire Front seat airbag assembly LH (Side squib LH) Airbag sensor assembly
B1828/56	The airbag sensor assembly receives a short circuit to B+ signal in the side squib LH circuit for 0.5 seconds Side squib LH malfunction Airbag sensor assembly malfunction	No. 2 floor wire Front seat airbag assembly LH (Side squib LH) 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

1.

CHECK DTC

(a) Proceed to the appropriate step according to DTC readings.

(1) If using the Techstream (read the 5-digit DTCs):

Using the Techstream, check for DTCs (See page ).

Result

Result	Proceed to
DTC B1825 is output.	A
DTC B1826 is output.	B
DTC B1827 is output.	C
DTC B1828 is output.	D

B

GO TO STEP 3

C

GO TO STEP 4

D

GO TO STEP 5

A

2.	CHECK NO. 2 FLOOR WIRE (FOR SHORT)

(a) Release the activation prevention mechanism built into connector B (See page ).

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
S26-1 (SFL+) - S26-2 (SFL-)	Always	1 MΩ or Higher

Text in Illustration

*1	Side Squib LH
*2	No. 2 Floor Wire
*3	Airbag Sensor Assembly

Result

Result	Proceed to
NG	A
OK	B

A

REPLACE NO. 2 FLOOR WIRE

B

GO TO STEP 6

3.	CHECK NO. 2 FLOOR WIRE (FOR OPEN)

(a) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition S26-1 (SFL+) - S26-2 (SFL-) Always Below 1 Ω Text in Illustration *1 Side Squib LH *2 No. 2 Floor Wire *3 Airbag Sensor Assembly

Result

Result	Proceed to
NG	A
OK	B

A

REPLACE NO. 2 FLOOR WIRE

B

GO TO STEP 7

4.	CHECK NO. 2 FLOOR WIRE (TO GROUND)

(a) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition S26-1 (SFL+) - Body ground Always 1 MΩ or Higher S26-2 (SFL-) - Body ground Always 1 MΩ or Higher Text in Illustration *1 Side Squib LH *2 No. 2 Floor Wire *3 Airbag Sensor Assembly

Result

Result	Proceed to
NG	A
OK	B

A

REPLACE NO. 2 FLOOR WIRE

B

GO TO STEP 7

5.	CHECK NO. 2 FLOOR WIRE (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
S26-1 (SFL+) - Body ground	Ignition switch ON	Below 1 V
S26-2 (SFL-) - Body ground	Ignition switch ON	Below 1 V

Text in Illustration

*1	Side Squib LH
*2	No. 2 Floor Wire
*3	Airbag Sensor Assembly

Result

Result	Proceed to
NG	A
OK	B

A

REPLACE NO. 2 FLOOR WIRE

B

GO TO STEP 7

6.	CHECK AIRBAG SENSOR ASSEMBLY

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

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

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

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

(e) Turn the ignition switch off.

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

(g) Check for DTCs (See page ).

OK:

DTC B1825 is not output.

Text in Illustration

*1	Side Squib LH
*2	Airbag Sensor Assembly

HINT:

DTCs other than B1825 may be output at this time, but they are not related to this check.

Result

Result	Proceed to
NG	A
OK	B

A

REPLACE AIRBAG SENSOR ASSEMBLY

B

GO TO STEP 8

7.	CHECK AIRBAG SENSOR ASSEMBLY

HINT:

If continuing from step 5, begin from (a). If continuing from any other step, begin from (c).

(a) Turn the ignition switch off.

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

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

(d) Using a service wire, connect S26-1 (SFL+) and S26-2 (SFL-) of connector C.

NOTICE:

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

(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 B1826, B1827 and B1828 are not output.

Text in Illustration

*1	Side Squib LH
*2	No. 2 Floor Wire
*3	Airbag Sensor Assembly
*4	Service Wire

HINT:

DTCs other than B1826, B1827 or B1828 may be output at this time, but they are not related to this check.

NG

REPLACE AIRBAG SENSOR ASSEMBLY

OK

8.	CHECK FRONT SEAT AIRBAG ASSEMBLY LH

HINT:

If continuing from step 9, begin from (c). If continuing from any other step, being from (a).

(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 service wire from connector C.

(d) Connect the connector to the front seat airbag assembly LH.

(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 B1825, B1826, B1827 and B1828 are not output.

Text in Illustration

*1	Side Squib LH
*2	Airbag Sensor Assembly

HINT:

DTCs other than B1825, B1826, B1827 or B1828 may be output at this time, but they are not related to this check.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE FRONT SEAT AIRBAG ASSEMBLY LH