SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: B1875/67-B1878/67; Short in Passenger Side Front Seat Cushion Squib Circuit; 2016 - 2020 MY Sienna [12/2015

Last Modified: 04-05-2023	6.11:8.1.0	Doc ID: RM100000000VJRI
Model Year Start: 2016	Model: Sienna	Prod Date Range: [12/2015 - ]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: B1875/67-B1878/67; Short in Passenger Side Front Seat Cushion Squib Circuit; 2016 - 2020 MY Sienna [12/2015 - ]

DTC

B1875/67

Short in Passenger Side Front Seat Cushion Squib Circuit

DTC

B1876/67

Open in Passenger Side Front Seat Cushion Squib Circuit

DTC

B1877/67

Short to GND in Passenger Side Front Seat Cushion Squib Circuit

DTC

B1878/67

Short to B+ in Passenger Side Front Seat Cushion Squib Circuit

DESCRIPTION

The passenger side front seat cushion squib circuit consists of the center airbag sensor assembly and front seat airbag sub-assembly RH.

The center airbag sensor assembly uses this circuit to deploy the airbag when deployment conditions are met. These DTCs are stored when a malfunction is detected in the passenger side front seat cushion squib circuit.

DTC No.	DTC Detection Condition	Trouble Area
B1875/67	The center airbag sensor assembly detects a line short in the passenger side front seat cushion squib circuit during primary check. Passenger side front seat cushion squib malfunction Center airbag sensor assembly malfunction	Floor wire Passenger side front seat cushion squib (Front seat airbag sub-assembly RH) Center airbag sensor assembly
B1876/67	The center airbag sensor assembly detects an open in the passenger side front seat cushion squib circuit. Passenger side front seat cushion squib malfunction Center airbag sensor assembly malfunction	Floor wire Passenger side front seat cushion squib (Front seat airbag sub-assembly RH) Center airbag sensor assembly
B1877/67	The center airbag sensor assembly detects a short to ground in the passenger side front seat cushion squib circuit. Passenger side front seat cushion squib malfunction Center airbag sensor assembly malfunction	Floor wire Passenger side front seat cushion squib (Front seat airbag sub-assembly RH) Center airbag sensor assembly
B1878/67	The center airbag sensor assembly detects a short to B+ in the passenger side front seat cushion squib circuit. Passenger side front seat cushion squib malfunction Center airbag sensor assembly malfunction	Floor wire Passenger side front seat cushion squib (Front seat airbag sub-assembly RH) Center 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 ).

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 road or rough road (See page ).

PROCEDURE

1.	CHECK CONNECTORS

(a) Turn the ignition switch off.

Text in Illustration

*1	Front Seat Airbag Sub-assembly RH
*2	Center Airbag Sensor Assembly
*3	Floor Wire

(b) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(c) Check that the connectors are properly connected to the front seat airbag sub-assembly RH and center airbag sensor assembly.

OK:

The connectors are properly connected.

HINT:

If the connectors are not properly connected, reconnect the connectors and proceed to the next inspection.

(d) Disconnect the connectors from the front seat airbag sub-assembly RH 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 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.

REPLACE FLOOR WIRE

2.	CHECK FRONT SEAT AIRBAG SUB-ASSEMBLY RH

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

Text in Illustration

*1	Front Seat Airbag Sub-assembly RH
*2	Center Airbag Sensor Assembly
*a	Front view of wire harness connector (to Front Seat Airbag Sub-assembly RH)

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

CAUTION:

Never connect a tester to the front seat airbag sub-assembly RH 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 it.
Insert SST straight into the terminals of the connector.

SST: 09843-18061

(d) Clear the DTCs stored in 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 B1875/67, B1876/67, B1877/67 or B1878/67 is not output.

HINT:

Codes other than DTCs B1875/67, B1876/67, B1877/67 and B1878/67 may be output at this time, but they are not related to this check.

(h) Turn the ignition switch off.

(i) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(j) Disconnect SST from connector C.

REPLACE FRONT SEAT AIRBAG SUB-ASSEMBLY RH

3.	CHECK FLOOR WIRE

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

(b) 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
L48-1 (FCP+) - Body ground	Ignition switch ON	Below 1 V
L48-2 (FCP-) - Body ground	Ignition switch ON	Below 1 V

Text in Illustration

*1	Front Seat Airbag Sub-assembly RH
*2	Center Airbag Sensor Assembly
*3	Floor Wire
*a	Front view of wire harness connector (to Front Seat Airbag Sub-assembly RH)

(4) Turn the ignition switch off.

(5) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
L48-1 (FCP+) - L48-2 (FCP-)	Always	Below 1 Ω

(d) 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
L48-1 (FCP+) - Body ground	Always	1 MΩ or higher
L48-2 (FCP-) - Body ground	Always	1 MΩ or higher

(e) 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
L48-1 (FCP+) - L48-2 (FCP-)	Always	1 MΩ or higher

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

REPLACE FLOOR WIRE

CHECK DTC

(a) Connect the connectors to the front seat airbag sub-assembly RH and center airbag sensor assembly.

Text in Illustration

*1	Front Seat Airbag Sub-assembly RH
*2	Center Airbag Sensor Assembly

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

(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:

DTC B1875/67, B1876/67, B1877/67 or B1878/67 is not output.

HINT:

Codes other than DTCs B1875/67, B1876/67, B1877/67 and B1878/67 may be output at this time, but they are not related to this check.

USE SIMULATION METHOD TO CHECK

REPLACE CENTER AIRBAG SENSOR ASSEMBLY