SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for TMMMS Made): B1855-B1858; Short in Rear Side Squib LH Circuit; 2021 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [04/2020

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM100000001NU76
Model Year Start: 2021	Model: GR Corolla	Prod Date Range: [04/2020 - 09/2022]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for TMMMS Made): B1855-B1858; Short in Rear Side Squib LH Circuit; 2021 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [04/2020 - 09/2022]

DTC

B1855

Short in Rear Side Squib LH Circuit

DTC

B1856

Open in Rear Side Squib LH Circuit

DTC

B1857

Short to GND in Rear Side Squib LH Circuit

DTC

B1858

Short to B+ in Rear Side Squib LH Circuit

DESCRIPTION

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

The 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 rear side squib LH circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Warning Indicate	Test Mode / Check Mode
B1855	Short in Rear Side Squib LH Circuit	The airbag sensor assembly detects a line short in the rear side squib LH circuit during the primary check. Rear side squib LH malfunction Airbag sensor assembly malfunction	Floor wire Rear side squib LH (Rear seat airbag assembly LH) Airbag sensor assembly	Comes on	Applies to check mode
B1856	Open in Rear Side Squib LH Circuit	The airbag sensor assembly detects an open in the rear side squib LH circuit. Rear side squib LH malfunction Airbag sensor assembly malfunction	Floor wire Rear side squib LH (Rear seat airbag assembly LH) Airbag sensor assembly	Comes on	Applies to check mode
B1857	Short to GND in Rear Side Squib LH Circuit	The airbag sensor assembly detects a short to ground in the rear side squib LH circuit. Rear side squib LH malfunction Airbag sensor assembly malfunction	Floor wire Rear side squib LH (Rear seat airbag assembly LH) Airbag sensor assembly	Comes on	Applies to check mode
B1858	Short to B+ in Rear Side Squib LH Circuit	The airbag sensor assembly detects a short to B+ in the rear side squib LH circuit. Rear side squib LH malfunction Airbag sensor assembly malfunction	Floor wire Rear side squib LH (Rear seat airbag assembly LH) Airbag sensor assembly	Comes on	Applies to check mode

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.

Click here

HINT:

Perform the simulation method by selecting check mode (Signal Check) using the Techstream.
Click here
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.
Click here

PROCEDURE

1.	CHECK CONNECTORS

(a) Turn the ignition switch off.

*1	Rear Seat Airbag Assembly LH
*2	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.

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 rear seat airbag assembly LH and airbag sensor assembly.

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

OK:

The terminals are not deformed or damaged.

(f) Check that the short springs of the activation prevention mechanism of the floor wire connector are not deformed or damaged.

OK:

The short springs are not deformed or damaged.

REPLACE FLOOR WIRE

2.	CHECK REAR SEAT AIRBAG ASSEMBLY LH

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

Rear Seat Airbag Assembly LH

Airbag Sensor Assembly

Front view of wire harness connector

(to Rear Seat Airbag Assembly LH)

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

CAUTION:

Never connect a tester to the rear seat airbag assembly 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 it.
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.

Body Electrical > SRS Airbag > Clear DTCs

(f) Turn the ignition switch off.

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

(h) Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B1855, B1856, B1857 or B1858 is not output.

HINT:

Codes other than DTCs B1855, B1856, B1857 and B1858 may be output at this time, but they are not related to this check.

(i) Turn the ignition switch off.

(j) 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.

(k) Disconnect SST from connector C.

REPLACE REAR SEAT AIRBAG ASSEMBLY LH

3.	CHECK FLOOR WIRE

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

*1	Rear Seat Airbag Assembly LH
*2	Airbag Sensor Assembly
*3	Floor Wire
*a	Front view of wire harness connector (to Rear Seat Airbag Assembly LH)

(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	Condition	Specified Condition
O141-1 (SRL+) - Body ground	Ignition switch ON	Below 1 V
O141-2 (SRL-) - Body ground	Ignition switch ON	Below 1 V

(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
O141-1 (SRL+) - O141-2 (SRL-)	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
O141-1 (SRL+) - Body ground	Always	1 MΩ or higher
O141-2 (SRL-) - 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.

Click here

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
O141-1 (SRL+) - O141-2 (SRL-)	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 rear seat airbag assembly LH and airbag sensor assembly.

*1	Rear Seat Airbag Assembly LH
*2	Airbag Sensor Assembly

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

(d) Clear the DTCs stored in memory.

Body Electrical > SRS Airbag > Clear DTCs

(e) Turn the ignition switch off.

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

(g) Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B1855, B1856, B1857 or B1858 is not output.

HINT:

Codes other than DTCs B1855, B1856, B1857 and B1858 may be output at this time, but they are not related to this check.

USE SIMULATION METHOD TO CHECK

REPLACE AIRBAG SENSOR ASSEMBLY