Nissan Sentra B18 (2020-2025) Service Manual: Fuel Level Sensor Signal Circuit

Component Function Check

1. COMBINATION METER INPUT SIGNAL

   1. CONSULT

      1. Select “FUEL METER” in “Data Monitor” mode of “METER/M&A”.

      2. Compare the “FUEL METER” value and the fuel gauge reading of the combination meter. Fuel gauge and data monitor indications should be close.

         Fuel gauge indication position	Reference value of data monitor [L]
         1	Approx. 45.8
         3/4	Approx. 35.4
         1/2	Approx. 24.6
         1/4	Approx. 12.4
         0	Approx. 2.9

   Does monitor value match fuel gauge reading?

   YES >>

   Inspection End.

   NO >>

   Replace combination meter. Refer to Removal and Installation.

Diagnosis Procedure

1. CHECK HARNESS CONNECTOR

   1. 1. Ignition switch OFF.

      2. Check combination meter and fuel level sensor unit and fuel pump (fuel level sensor) terminals (meter-side and harness-side) for poor connection.

   Is the inspection result normal?

   YES >>

   GO TO 2.

   NO >>

   Repair or replace harness or connector.

2. CHECK FUEL LEVEL SENSOR UNIT CIRCUIT

   1. 1. Disconnect combination meter harness connector and fuel level sensor unit and fuel pump (fuel level sensor) harness connector.

      2. Check continuity between combination meter harness connector and fuel level sensor unit and fuel pump (fuel level sensor) harness connector.

         Combination meter		Fuel level sensor unit and fuel pump (fuel level sensor)		Continuity
         Connector	Terminal	Connector	Terminal
         M24	35	B48	3	Yes

      3. Check continuity between fuel level sensor unit and fuel pump (fuel level sensor) harness connector and ground.

         Fuel level sensor unit and fuel pump (fuel level sensor)		—	Continuity
         Connector	Terminal
         B48	3	Ground	No

   Is the inspection result normal?

   YES >>

   GO TO 3.

   NO >>

   Repair or replace harness or connector.

3. CHECK FUEL LEVEL SENSOR GROUND CIRCUIT

   1. 1. Check continuity between combination meter harness connector and fuel level sensor unit and fuel pump (fuel level sensor) harness connector.

         Combination meter		Fuel level sensor unit and fuel pump (fuel level sensor)		Continuity
         Connector	Terminal	Connector	Terminal
         M24	36	B48	2	Yes

      2. Check continuity between fuel level sensor unit and fuel pump (fuel level sensor) harness connector and ground.

         Fuel level sensor unit and fuel pump (fuel level sensor)		—	Continuity
         Connector	Terminal
         B48	2	Ground	No

   Is the inspection result normal?

   YES>>

   GO TO 4.

   NO>>

   Repair or replace harness or connector.

4. CHECK INSTALLATION CONDITION

   1. Check fuel level sensor unit installation, and verify the float arm does not interfere or bind with the internal components in the fuel tank.

   Is the inspection result normal?

   YES >>

   Inspection End.

   NO >>

   Install the fuel level sensor unit and fuel pump (fuel level sensor) properly. Refer to Removal and Installation.

Component Inspection

1. CHECK FUEL LEVEL SENSOR UNIT AND FUEL PUMP (FUEL LEVEL SENSOR)

   1. 1. Remove the fuel level sensor unit and fuel pump (fuel level sensor). Refer to Removal and Installation.

      2. Check the resistance between fuel level sensor unit and fuel pump (fuel level sensor) terminals.

         

         Fuel level sensor unit and fuel pump (fuel level sensor)		Condition	Resistance (Ω) (Approx.)	Height [mm (in)]
         Terminals
         2	3	Full* (A)	91	144 (5.67)
         		Empty* (B)	283.0	19 (0.75)

         *: When float rod is contact with stopper.

   Is the inspection result normal?

   YES >>

   Inspection End.

   NO >>

   Replace fuel level sensor unit and fuel pump (fuel level sensor). Refer to Removal and Installation.

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