DTC B1656: Seat Belt Buckle Switch (LH) [08/2020 - ]: Procedure

WARNING: This page is about a different car, the 2025 Toyota RAV4, 2024 Toyota RAV4, 2023 Toyota RAV4, 2022 Toyota RAV4, and 2021 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.

CHECK CONNECTION OF CONNECTORS

Turn the ignition switch off.
Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.

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

Result

Proceed to
Connectors are properly connected
Connectors are not properly connected

Result:

Connectors are not properly connected

CONNECT CONNECTORS PROPERLY

Result:

Connectors are properly connected

See step 2

CHECK CONNECTORS

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

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*1	Front Seat Inner Belt Assembly LH
*2	Airbag ECU Assembly
*3	Floor Wire

Check that the connectors (on the airbag ECU assembly side and front seat inner belt assembly LH side) are not damaged.

Result

Proceed to
Connectors are not deformed or damaged
Connectors are deformed or damaged

Result:

Connectors are deformed or damaged

REPLACE FLOOR WIRE

Result:

Connectors are not deformed or damaged

See step 3

CHECK FLOOR WIRE

Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Turn the ignition switch to ON.

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
N35-1 (LBE-) - Body ground	Ignition switch ON	Below 1 V
N35-2 (LBE+) - Body ground	Ignition switch ON	Below 1 V

Turn the ignition switch off.
Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
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 a service wire.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
N35-1 (LBE-) - N35-2 (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
N35-1 (LBE-) - N35-2 (LBE+)	Always	1 MΩ or higher
N35-1 (LBE-) - Body ground	Always	1 MΩ or higher
N35-2 (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 ECU assembly and front seat inner belt assembly LH.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
Turn the ignition switch to ON, and wait for at least 60 seconds.
Clear the DTCs stored in memory.
Refer to DTC CHECK / CLEAR [08/2020 - ]

Body Electrical > SRS Airbag > Clear DTCs
Turn the ignition switch off.
Turn the ignition switch to ON, and wait for at least 60 seconds.

Check for DTCs.

Refer to DTC CHECK / CLEAR [08/2020 - ]

Body Electrical > SRS Airbag > Trouble Codes

Result

Proceed to
DTC B1656 is not output
DTC B1656 is output

HINT:

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

Result:

DTC B1656 is not output

USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2018 - ]

Result:

DTC B1656 is output

See step 5

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH

Turn the ignition switch off.
Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.

Replace the front seat inner belt assembly LH.

for Manual Seat:

Refer to REMOVAL [08/2020 - 12/2021] , or refer to REMOVAL [12/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]

for Power Seat:

Refer to REMOVAL [08/2020 - 12/2021] , or refer to REMOVAL [12/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]

HINT:

Perform the inspection using parts from a normal vehicle if possible.

Result

Proceed to
NEXT

Result:

See step 6

CHECK DTC

Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.

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

Turn the ignition switch to ON, and wait for at least 60 seconds.
Clear the DTCs stored in memory.
Refer to DTC CHECK / CLEAR [08/2020 - ]

Body Electrical > SRS Airbag > Clear DTCs
Turn the ignition switch off.
Turn the ignition switch to ON, and wait for at least 60 seconds.

Check for DTCs.

Refer to DTC CHECK / CLEAR [08/2020 - ]

Body Electrical > SRS Airbag > Trouble Codes

Result

Proceed to
DTC B1656 is not output
DTC B1656 is output

HINT:

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

Result:

DTC B1656 is not output

END (FRONT SEAT INNER BELT ASSEMBLY LH WAS DEFECTIVE)

Result:

DTC B1656 is output

REPLACE AIRBAG ECU ASSEMBLY. Refer to REMOVAL [08/2020 - 12/2021] , or refer to REMOVAL [12/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]