Toyota Tacoma (2015-2018) Service Manual: Short in Side Squib RH Circuit (B1820/55-B1823/55)

DESCRIPTION

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

The 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 RH circuit.

DTC No.	DTC Detecting Conditions	Trouble Areas
B1820/55	The airbag sensor assembly receives a line short circuit signal in the side squib RH circuit for 2 seconds side squib RH malfunction Airbag sensor assembly malfunction	Floor wire Front seat airbag assembly RH (Side squib RH) Airbag sensor assembly
B1821/55	The airbag sensor assembly receives an open circuit signal in the side squib RH circuit for 2 seconds side squib RH malfunction Airbag sensor assembly malfunction	Floor wire Front seat airbag assembly RH (Side squib RH) Airbag sensor assembly
B1822/55	The airbag sensor assembly receives a short circuit to ground signal in the side squib RH circuit for 0.5 seconds side squib RH malfunction Airbag sensor assembly malfunction	Floor wire Front seat airbag assembly RH (Side squib RH) Airbag sensor assembly
B1823/55	The airbag sensor assembly receives a short circuit to B+ signal in the side squib RH circuit for 0.5 seconds side squib RH malfunction Airbag sensor assembly malfunction	Floor wire Front seat airbag assembly RH (Side squib RH) 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 B1820 is output.	A
DTC B1821 is output.	B
DTC B1822 is output.	C
DTC B1823 is output.	D

B

GO TO STEP 3

C

GO TO STEP 4

D

GO TO STEP 5

A

2.	CHECK 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
S27-1 (SFR+) - S27-2 (SFR-)	Always	1 MΩ or Higher

Text in Illustration

*1	Side Squib RH
*2	Floor Wire
*3	Airbag Sensor Assembly

Result

Result	Proceed to
NG	A
OK	B

A

REPLACE FLOOR WIRE

B

GO TO STEP 6

3.	CHECK FLOOR WIRE (FOR OPEN)

(a) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition S27-1 (SFR+) - S27-2 (SFR-) Always Below 1 Ω Text in Illustration *1 Side Squib RH *2 Floor Wire *3 Airbag Sensor Assembly

Result

Result	Proceed to
NG	A
OK	B

A

REPLACE FLOOR WIRE

B

GO TO STEP 7

4.	CHECK FLOOR WIRE (TO GROUND)

(a) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition S27-1 (SFR+) - Body ground Always 1 MΩ or Higher S27-2 (SFR-) - Body ground Always 1 MΩ or Higher Text in Illustration *1 Side Squib RH *2 Floor Wire *3 Airbag Sensor Assembly

Result

Result	Proceed to
NG	A
OK	B

A

REPLACE FLOOR WIRE

B

GO TO STEP 7

5.	CHECK 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
S27-1 (SFR+) - Body ground	Ignition switch ON	Below 1 V
S27-2 (SFR-) - Body ground	Ignition switch ON	Below 1 V

Text in Illustration

*1	Side Squib RH
*2	Floor Wire
*3	Airbag Sensor Assembly

Result

Result	Proceed to
NG	A
OK	B

A

REPLACE 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 B1820 is not output.

Text in Illustration

*1	Side Squib RH
*2	Airbag Sensor Assembly

HINT:

DTCs other than B1820 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 S27-1 (SFR+) and S27-2 (SFR-) 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 the 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 B1821, B1822 and B1823 are not output.

Text in Illustration

*1	Side Squib RH
*2	Floor Wire
*3	Airbag Sensor Assembly
*4	Service Wire

HINT:

DTCs other than B1821, B1822 or B1823 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 RH

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 RH (Side squib RH).

(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 B1820, B1821, B1822 and B1823 are not output.

Text in Illustration

*1	Side Squib RH
*2	Airbag Sensor Assembly

HINT:

DTCs other than B1820, B1821, B1822 or B1823 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 RH