Nissan Sentra B18 (2020-2025) Service Manual: Diagnosis Procedure

Nissan Sentra B18 (2020-2025) Service Manual / Driver Information & Multimedia / Warning Chime System :: Dtc/circuit Diagnosis / Front Seat Belt Buckle Switch Lh Signal Circuit / Diagnosis Procedure

Diagnosis Procedure

CHECK BCM INPUT SIGNAL

Ignition switch ON.

Check voltage between BCM harness connector and ground.

(+)		(-)	Condition	Voltage (Approx.)
BCM
Connector	Terminal
M84	17	Ground	When driver seat belt is fastened	Battery voltage
M84	17	Ground	When driver seat belt is unfastened	0 V

Is the inspection result normal?

YES>>

Replace BCM. Refer to Removal and Installation.

NO>>

GO TO 2.

CHECK FRONT SEAT BELT BUCKLE SWITCH LH CIRCUIT

Ignition switch OFF.
Disconnect BCM harness connector and front seat belt buckle switch LH harness.

Check continuity between BCM harness connector and front seat belt buckle switch LH harness connector.

BCM		Front seat belt buckle switch LH		Continuity
Connector	Terminal	Connector	Terminal	Continuity
M84	17	B57	1	Yes

Check continuity between BCM harness connector and ground.

BCM		—	Continuity
Connector	Terminal	—	Continuity
M84	17	Ground	No

Is the inspection result normal?

YES>>

GO TO 3.

NO>>

Repair or replace harness or connectors.

CHECK FRONT SEAT BELT BUCKLE SWITCH LH GROUND CIRCUIT

Check harness continuity between front seat belt buckle switch LH harness connector and ground.

Front seat belt buckle switch LH		—	Continuity
Connector	Terminal	—	Continuity
B57	2	Ground	Yes

Is the inspection result normal?

YES>>

Check the front seat belt buckle switch. Refer to Component Inspection.

NO>>

Repair or replace harness or connectors.

Component Function Check

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Component Inspection

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