DTC B1656: Seat Belt Buckle Switch (LH) [01/2019 - 09/2022]: Procedure

WARNING: This page is about a different variant/trim than selected.

CHECK CONNECTION OF CONNECTORS

Turn the power switch off.
Disconnect the cable from the negative (-) auxiliary battery terminal.
WARNING:
Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

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

The connectors are properly connected.

Result

Proceed to
OK
NG

Result:

CONNECT CONNECTORS PROPERLY

Result:

See step 2

CHECK CONNECTORS

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

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

The terminals are not deformed or damaged.

Result

Proceed to
OK
NG

Result:

REPLACE FLOOR WIRE OR FRONT SEAT INNER BELT ASSEMBLY LH

Result:

See step 3

CHECK FLOOR WIRE

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

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*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)

Turn the power switch on (IG).

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

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

Turn the power switch off.
Disconnect the cable from the negative (-) auxiliary battery terminal.
WARNING:
Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.
Using a service wire, connect terminals 28 (LBE+) and 27 (LBE-) of connector B.
NOTE:
Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.

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

Disconnect the service wire from connector B.

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

Result

Proceed to
OK
NG

Result:

REPLACE FLOOR WIRE

Result:

See step 4

CHECK DTC

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

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Connect the cable to the negative (-) auxiliary battery terminal.
Turn the power switch on (IG), and wait for at least 60 seconds.
Clear the DTCs stored in memory.
Body Electrical > SRS Airbag > Clear DTCs
Turn the power switch off.
Turn the power switch on (IG), and wait for at least 60 seconds.

Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

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.

Result

Result
OK
NG

Result:

USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ]

Result:

See step 5

CHECK FRONT SEAT INNER BELT ASSEMBLY LH

Turn the power switch off.

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

Disconnect the cable from the negative (-) auxiliary battery terminal.
WARNING:
Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.
Replace the front seat inner belt assembly LH with a known good one.
Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

HINT:

Perform the following inspection using known good parts from another vehicle if possible.
Connect the cable to the negative (-) auxiliary battery terminal.
Turn the power switch on (IG), and wait for at least 60 seconds.
Clear the DTCs stored in memory.
Body Electrical > SRS Airbag > Clear DTCs
Turn the power switch off.
Turn the power switch on (IG), and wait for at least 60 seconds.
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.
Turn the power switch off.
Disconnect the cable from the negative (-) auxiliary battery terminal.
WARNING:
Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

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

Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

Result

Proceed to
OK
NG

Result:

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH. Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

Result:

REPLACE AIRBAG SENSOR ASSEMBLY. Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]