Toyota 4Runner: Short in Front Passenger Side Squib 2nd Step Circuit (B1815/54-B1818/54)

Toyota 4Runner Service Manual / Vehicle Interior / Supplemental Restraint Systems / Airbag System / Short in Front Passenger Side Squib 2nd Step Circuit (B1815/54-B1818/54)

DESCRIPTION

The front passenger side squib 2nd step circuit consists of the center airbag sensor and instrument panel passenger airbag.

The circuit instructs the SRS to deploy when deployment conditions are met.

These DTCs are stored when a malfunction is detected in the front passenger side squib 2nd step circuit.

DTC Code	DTC Detection Condition	Trouble Area
B1815/54	One of the following conditions is met: The center airbag sensor detects a line short circuit signal 5 times in the front passenger side squib 2nd step circuit during the primary check. A front passenger side squib 2nd step malfunction. A center airbag sensor malfunction.	Instrument panel wire No. 2 instrument panel wire Instrument panel passenger airbag assembly (Front passenger side squib 2nd step) Center airbag sensor assembly
B1816/54	One of the following conditions is met: The center airbag sensor detects an open circuit signal in the front passenger side squib 2nd step circuit for 2 seconds. A front passenger side squib 2nd step malfunction. A center airbag sensor malfunction.	Instrument panel wire No. 2 instrument panel wire Instrument panel passenger airbag assembly (Front passenger side squib 2nd step) Center airbag sensor assembly
B1817/54	One of the following conditions is met: The center airbag sensor detects a short circuit to ground signal in the front passenger side squib 2nd step circuit for 0.5 seconds. A front passenger side squib 2nd step malfunction. A center airbag sensor malfunction.	Instrument panel wire No. 2 instrument panel wire Instrument panel passenger airbag assembly (Front passenger side squib 2nd step) Center airbag sensor assembly
B1818/54	One of the following conditions is met: The center airbag sensor detects a short circuit to B+ signal in the front passenger side squib 2nd step circuit for 0.5 seconds. A front passenger side squib 2nd step malfunction. A center airbag sensor malfunction.	Instrument panel wire No. 2 instrument panel wire Instrument panel passenger airbag assembly (Front passenger side squib 2nd step) 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 ).

HINT:

To perform the simulation method, enter check mode (signal check) with the Techstream (See page ), and then wiggle each connector of
the airbag system or drive the vehicle on various types of road (See page ).

PROCEDURE

1.	CHECK INSTRUMENT PANEL PASSENGER AIRBAG (FRONT PASSENGER SIDE SQUIB 2ND STEP)

(a) Turn the ignition switch off.

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

(d) Connect the white wire side of SST (resistance: 2.1 Ω) to connector E (black connector).

CAUTION:

Never connect the tester to the instrument panel passenger airbag (front passenger side squib 2nd step) for measurement, as this may lead to a serious injury due to airbag deployment.

NOTICE:

Do not forcibly insert SST into the terminals of the connector when connecting SST.
Insert SST straight into the terminals of the connector.

SST: 09843-18061

(e) Connect the cable to the negative (-) battery terminal, 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 (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 B1815, B1816, B1817 or B1818 is not output.

HINT:

Codes other than DTC B1815, B1816, B1817 and B1818 may be output at this time, but they are not related to this check.

Text in Illustration

*1	Front Passenger Side Squib 2nd Step
*2	Center Airbag Sensor
*3	Connector E
*4	SST
*a	Front view of wire harness connector (to Front Passenger Side Squib 2nd Step)
*b	Color: Black

REPLACE INSTRUMENT PANEL PASSENGER AIRBAG ASSEMBLY

2.	CHECK CONNECTOR

(a) Turn the ignition switch off.

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

(d) Check that the instrument panel wire connectors (on the instrument panel passenger airbag side) are not damaged.

OK:

The lock button is not disengaged, and the claw of the lock is not damaged or deformed.

Text in Illustration

*1	Front Passenger Side Squib 2nd Step
*2	Center Airbag Sensor

REPLACE NO. 2 INSTRUMENT PANEL WIRE

3.	CHECK FRONT PASSENGER SIDE SQUIB 2ND STEP CIRCUIT

(a) Disconnect the connectors from the center airbag sensor.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
z2-1 (P2+) - Body ground	Ignition switch ON	Below 1 V
z2-2 (P2-) - 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) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-1 (P2+) - z2-2 (P2-)	Always	Below 1 Ω

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-1 (P2+) - z2-2 (P2-)	Always	1 MΩ or higher
z2-1 (P2+) - Body ground	Always	1 MΩ or higher
z2-2 (P2-) - Body ground	Always	1 MΩ or higher

Text in Illustration

*1	Front Passenger Side Squib 2nd Step
*2	Center Airbag Sensor
*3	Connector E
*a	Front view of wire harness connector (to Front Passenger Side Squib 2nd Step)
*b	Color: Black

GO TO STEP 5

4.	CHECK CENTER AIRBAG SENSOR

(a) Connect the connectors to the instrument panel passenger airbag and center airbag sensor.

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

(d) Clear the DTCs (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 B1815, B1816, B1817 or B1818 is not output.

HINT:

Codes other than DTC B1815, B1816, B1817 and B1818 may be output at this time, but they are not related to this check.

Text in Illustration

*1	Front Passenger Side Squib 2nd Step
*2	Center Airbag Sensor

USE SIMULATION METHOD TO CHECK

REPLACE CENTER AIRBAG SENSOR ASSEMBLY

5.	CHECK INSTRUMENT PANEL WIRE (CENTER AIRBAG SENSOR - NO. 2 INSTRUMENT PANEL WIRE)

(a) Restore the released activation prevention mechanism of connector B to its original condition.

(b) Disconnect the instrument panel wire connector from the No. 2 instrument panel wire.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
Fz1-3 - Body ground	Ignition switch ON	Below 1 V
Fz1-4 - Body ground	Ignition switch ON	Below 1 V

(e) Turn the ignition switch off.

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
Fz1-3 - Fz1-4	Always	Below 1 Ω

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
Fz1-3 - Fz1-4	Always	1 MΩ or higher
Fz1-3 - Body ground	Always	1 MΩ or higher
Fz1-4 - Body ground	Always	1 MΩ or higher

Text in Illustration

*1	Front Passenger Side Squib 2nd Step
*2	No. 2 Instrument Panel Wire
*3	Instrument Panel Wire
*4	Center Airbag Sensor
*5	Connector C
*a	Front view of wire harness connector (to No. 2 Instrument Panel Wire)

REPLACE NO. 2 INSTRUMENT PANEL WIRE

REPLACE INSTRUMENT PANEL WIRE

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