Toyota Venza: Short in Front Pretensioner Squib LH Circuit (B1905/74-B1908/74)

Toyota Venza Service Manual / Supplemental Restraint Systems / Airbag System / Short in Front Pretensioner Squib LH Circuit (B1905/74-B1908/74)

DESCRIPTION

The front pretensioner squib LH circuit consists of the center airbag sensor assembly and front seat outer belt assembly LH.

The center airbag sensor assembly uses this circuit to deploy the seat belt pretensioner when deployment conditions are met.

These DTCs are stored when a malfunction is detected in the front pretensioner squib LH circuit.

DTC No.	DTC Detection Condition	Trouble Area
B1905/74	The center airbag sensor assembly receives a line short circuit signal in the front pretensioner squib LH circuit during primary check. Front pretensioner squib LH malfunction Center airbag sensor assembly malfunction	Floor wire Front seat outer belt assembly LH (Front pretensioner squib LH) Center airbag sensor assembly
B1906/74	The center airbag sensor assembly receives an open circuit signal in the front pretensioner squib LH circuit. Front pretensioner squib LH malfunction Center airbag sensor assembly malfunction	Floor wire Front seat outer belt assembly LH (Front pretensioner squib LH) Center airbag sensor assembly
B1907/74	The center airbag sensor assembly receives a short circuit to ground signal in the front pretensioner squib LH circuit. Front pretensioner squib LH malfunction Center airbag sensor assembly malfunction	Floor wire Front seat outer belt assembly LH (Front pretensioner squib LH) Center airbag sensor assembly
B1908/74	The center airbag sensor assembly receives a short circuit to B+ signal in the front pretensioner squib LH circuit. Front pretensioner squib LH malfunction Center airbag sensor assembly malfunction	Floor wire Front seat outer belt assembly LH (Front pretensioner squib LH) Center airbag sensor assembly

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

Perform the simulation method by selecting check mode (Signal Check) using the Techstream (See page ).
After selecting check mode (Signal Check), perform the simulation method by wiggling each connector of the airbag system or driving the vehicle on a city or rough road (See page ).

PROCEDURE

1.	CHECK CONNECTORS

(a) Turn the ignition switch off.

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

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

OK:

The connectors are properly connected.

HINT:

If the connectors are connected securely, reconnect the connectors and proceed to the next inspection.

(d) Disconnect the connectors from the front seat outer belt assembly LH and center airbag sensor assembly.

(e) Check that the terminals of the connectors are not damaged.

OK:

The terminals are not deformed or damaged.

(f) Check that the floor wire connector (on the front seat outer belt assembly LH side) is not damaged.

OK:

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

(g) Check that the short spring for the floor wire with the activation prevention mechanism is not deformed or damaged.

OK:

The short spring is not deformed or damaged.

Text in Illustration

*1	Front Pretensioner Squib LH
*2	Center Airbag Sensor Assembly
*3	Floor Wire

REPLACE FLOOR WIRE

2.	CHECK FRONT SEAT OUTER BELT ASSEMBLY LH (FRONT PRETENSIONER SQUIB LH)

(a) Connect the connector to the center airbag sensor assembly.

(b) Connect SST (resistance 2.1 Ω) to connector C.

CAUTION:

Never connect an electrical tester to the front seat outer belt assembly LH (front pretensioner squib LH) 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.
Insert SST straight into the terminals of the connector.

SST: 09843-18061

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

(e) Clear the DTCs stored in 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 ).

OK:

DTC B1905, B1906, B1907, B1908 or 74 is not output.

Text in Illustration

*1	Front Pretensioner Squib LH
*2	Center Airbag Sensor Assembly
*3	Front view of wire harness connector (to Front Seat Outer Belt Assembly LH)
*4	Connector C

HINT:

Codes other than DTCs B1905, B1906, B1907, B1908 and 74 may be output at this time, but they are not related to this check.

REPLACE FRONT SEAT OUTER BELT ASSEMBLY LH

3.	CHECK FLOOR WIRE (FRONT PRETENSIONER SQUIB LH CIRCUIT)

(a) Turn the ignition switch off.

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

(d) Disconnect the floor wire from the center airbag sensor assembly.

(e) Check for a short to B+ in the circuit.

(1) Connect the cable to the negative (-) battery terminal.

(2) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
L6-1 (L+) - Body ground	Ignition switch ON	Below 1 V
L6-2 (L-) - Body ground	Ignition switch ON	Below 1 V

(f) Check for an open in the circuit.

(1) Turn the ignition switch off.

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
L6-1 (L+) - L6-2 (L-)	Always	Below 1 Ω

(g) Check for a short to ground in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
L6-1 (L+) - Body ground	Always	1 MΩ or higher
L6-2 (L-) - Body ground	Always	1 MΩ or higher

(h) Check for a short in the circuit.

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
L6-1 (L+) - L6-2 (L-)	Always	1 MΩ or higher

Text in Illustration

*1	Front Pretensioner Squib LH
*2	Center Airbag Sensor Assembly
*3	Floor Wire
*4	Front view of wire harness connector (to Front Seat Outer Belt Assembly LH)
*5	Connector C

REPLACE FLOOR WIRE

4.	CHECK CENTER AIRBAG SENSOR ASSEMBLY

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

(b) Connect the connectors to the front seat outer belt assembly LH and center airbag sensor assembly.

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

(e) Clear the DTCs stored in 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 ).

OK:

DTC B1905, B1906, B1907, B1908 or 74 is not output.

Text in Illustration

*1	Front Pretensioner Squib LH
*2	Center Airbag Sensor Assembly

HINT:

Codes other than DTCs B1905, B1906, B1907, B1908 and 74 may be output at this time, but they are not related to this check.

USE SIMULATION METHOD TO CHECK

REPLACE CENTER AIRBAG SENSOR ASSEMBLY

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