DTC B0050-00: Driver Seat Belt Sensor Circuit Undetermined Failure [11/2020 - 12/2022]: Procedure

CHECK CONNECTION OF CONNECTORS

Pre-procedure1

Turn the ignition switch off.
Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.

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

The connectors are properly connected.

Result

Proceed to
OK
NG

Post-procedure1

None

Result:

CONNECT CONNECTORS PROPERLY

Result:

See step 2

CHECK CONNECTORS

Pre-procedure1

Disconnect the airbag ECU assembly connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Disconnect the front seat inner belt assembly LH connector.

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

The terminals of the connectors are not deformed or damaged.

Result

Proceed to
OK
NG

Post-procedure1

None

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 3

INSPECT FRONT SEAT INNER BELT ASSEMBLY LH

Pre-procedure1

Remove the front seat inner belt assembly LH.
HINT:

Refer to REMOVAL [11/2020 - 11/2021] , or refer to REMOVAL [11/2021 - 12/2022]

Inspect the front seat inner belt assembly LH.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*1	Front Seat Inner Belt Assembly LH	*2	Battery
*a	Component without harness connected (Front Seat Inner Belt Assembly LH)	*b	Tester

Standard Current

Tester Connection	Condition	Specified Condition	Result
Tester positive (+) - 2 (LBE+) Tester negative (-) - Battery negative (-)	Seat belt fastened	12.0 to 18.0 mA	mA
Tester positive (+) - 2 (LBE+) Tester negative (-) - Battery negative (-)	Seat belt not fastened	4.0 to 7.0 mA	mA

Result

Proceed to
OK
NG

Post-procedure1

None

Result:

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH. Refer to REMOVAL [11/2020 - 11/2021] , or refer to REMOVAL [11/2021 - 12/2022]

Result:

See step 4

CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT TO GROUND IN THE CIRCUIT)

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

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Result
G23-2 (LBE+) - Body ground	Always	1 MΩ or higher	MΩ
G23-1 (LBE-) - Body ground	Always	1 MΩ or higher	MΩ

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 5

CHECK HARNESS AND CONNECTOR (CHECK FOR OPEN IN THE CIRCUIT)

Pre-procedure1

Using a service wire, connect terminals 30 (LBE+) and 24 (GNDL) of connector B.

NOTE:

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

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Result
G23-2 (LBE+) - G23-1 (LBE-)	Always	Below 1 Ω	Ω

Result

Proceed to
OK
NG

Post-procedure1

Disconnect the service wire from connector B.

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 6

CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT TO +B IN THE CIRCUIT)

Pre-procedure1

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	Wire Harness
*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	Result
G23-2 (LBE+) - Body ground	Ignition switch ON	Below 1 V	V
G23-1 (LBE-) - Body ground	Ignition switch ON	Below 1 V	V

Result

Proceed to
OK
NG

Post-procedure1

Turn the ignition switch off.
Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 7

CLEAR DTC

Connect the airbag ECU assembly connector.

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

Connect the front seat inner belt assembly LH connector.
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.

Body Electrical > SRS Airbag > Clear DTCs

Result

Proceed to
NEXT

Result:

See step 8

CHECK DTC

Pre-procedure1

Turn the ignition switch off.
Turn the ignition switch to ON, and wait for at least 60 seconds.

Check for DTCs.

Body Electrical > SRS Airbag > Trouble Codes

Result

Result	Proceed to
B0050-00 is not output	A
B0050-00 is output	B

Post-procedure1

None

Result:

USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2020 - ]

Result:

REPLACE AIR BAG ECU ASSEMBLY. Refer to REMOVAL [11/2020 - 11/2021] , or refer to REMOVAL [11/2021 - 12/2022]