SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for HV Model): B1656; Seat Belt Buckle Switch (LH); 2020 - 2022 MY Corolla Corolla HV [01/2019

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM100000001G4PT
Model Year Start: 2020	Model: Corolla	Prod Date Range: [01/2019 - 09/2022]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (for HV Model): B1656; Seat Belt Buckle Switch (LH); 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

DTC

B1656

Seat Belt Buckle Switch (LH)

DESCRIPTION

The front seat belt buckle switch LH circuit consists of the airbag sensor assembly and front seat belt buckle switch LH (front seat inner belt assembly LH).

DTC B1656 is stored when a malfunction is detected in the front seat belt buckle switch LH circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Warning Indicate	Test Mode / Check Mode
B1656	Seat Belt Buckle Switch (LH)	The airbag sensor assembly detects a line short, short to ground or B+, or an open in the front seat belt buckle switch LH circuit. Front seat belt buckle switch LH malfunction Airbag sensor assembly malfunction	Floor wire Front seat belt buckle switch LH (Front seat inner belt assembly LH) Airbag sensor assembly	Comes on	Does not apply to test/check mode

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

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PROCEDURE

1.	CHECK CONNECTION OF CONNECTORS

(a) Turn the power switch off.

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

CAUTION:

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

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

OK:

The connectors are properly connected.

CONNECT CONNECTORS PROPERLY

2.	CHECK CONNECTORS

(a) Disconnect the connectors from the airbag sensor assembly and front seat inner belt assembly LH.

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

OK:

The terminals are not deformed or damaged.

REPLACE FLOOR WIRE OR FRONT SEAT INNER BELT ASSEMBLY LH

3.	CHECK FLOOR WIRE

(a) Connect the cable to the negative (-) auxiliary battery terminal.

*1	Front Seat Inner Belt Assembly LH
*2	Airbag Sensor Assembly
*3	Floor Wire
*4	Service Wire
*a	Front view of wire harness connector (to Airbag Sensor Assembly)
*b	Front view of wire harness connector (to Front Seat Inner Belt Assembly LH)

(b) Turn the power switch on (IG).

Standard Voltage:

Tester Connection	Condition	Specified Condition
O23-2 (LBE+) - Body ground	Power switch on (IG)	Below 1 V
O23-1 (LBE-) - Body ground	Power switch on (IG)	Below 1 V

(d) Turn the power switch off.

(e) Disconnect the cable from the negative (-) auxiliary battery terminal.

CAUTION:

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

(f) Using a service wire, connect terminals 28 (LBE+) and 27 (LBE-) of connector B.

NOTICE:

Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
O23-2 (LBE+) - O23-1 (LBE-)	Always	Below 1 Ω

(h) Disconnect the service wire from connector B.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
O23-2 (LBE+) - O23-1 (LBE-)	Always	1 MΩ or higher
O23-2 (LBE+) - Body ground	Always	1 MΩ or higher
O23-1 (LBE-) - Body ground	Always	1 MΩ or higher

REPLACE FLOOR WIRE

CHECK DTC

(a) Connect the connectors to the airbag sensor assembly and front seat inner belt assembly LH.

*1	Front Seat Inner Belt Assembly LH
*2	Airbag Sensor Assembly

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

(d) Clear the DTCs stored in memory.

Body Electrical > SRS Airbag > Clear DTCs

(e) Turn the power switch off.

(f) Turn the power switch on (IG), and wait for at least 60 seconds.

(g) Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B1656 is not output.

HINT:

Codes other than DTC B1656 may be output at this time, but they are not related to this check.

USE SIMULATION METHOD TO CHECK

5.	CHECK FRONT SEAT INNER BELT ASSEMBLY LH

(a) Turn the power switch off.

*1	Front Seat Inner Belt Assembly LH
*2	Airbag Sensor Assembly

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

CAUTION:

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

Click here

HINT:

Perform the following inspection using known good parts from another vehicle if possible.

(d) Connect the cable to the negative (-) auxiliary battery terminal.

(e) Turn the power switch on (IG), and wait for at least 60 seconds.

(f) Clear the DTCs stored in memory.

Body Electrical > SRS Airbag > Clear DTCs

(g) Turn the power switch off.

(h) Turn the power switch on (IG), and wait for at least 60 seconds.

(i) Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B1656 is not output.

HINT:

Codes other than DTC B1656 may be output at this time, but they are not related to this check.

(j) Turn the power switch off.

(k) Disconnect the cable from the negative (-) auxiliary battery terminal.

CAUTION:

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

(l) Restore the front seat inner belt assembly LH that was installed for testing to its original location.

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REPLACE FRONT SEAT INNER BELT ASSEMBLY LH

REPLACE AIRBAG SENSOR ASSEMBLY