Fuel Level Sensor Signal Inspection

Symptom:

• Improper fuel gauge indication.
• Low-fuel warning lamp indication is irregular.

• Depending on vehicle position or driving circumstance, the fuel level in the tank shifts and the indication may fluctuate.
• If the vehicle is fueled with the ignition switch ON, the indication will update slowly.
• If the vehicle is tilted when the ignition switch is turned ON, fuel in the tank may flow to one direction resulting in a change of reading.

1. CHECK COMBINATION METER INPUT SIGNAL
   1. Select "METER/M&A" on CONSULT-III.
   2. Using "FUEL METER" on "DATA MONITOR", compare the value of "DATA MONITOR" with fuel gauge indication of combination meter.
      FUEL GAUGE REFERENCE
      
      

      Fuel gauge indication (approx. segments)	Reference value of data monitor [lit.]
      Full (13)	Approx. 55
      3/4 (10)	Approx. 38
      1/2 (7)	Approx. 25
      1/4 (4)	Approx. 13
      Empty (0)	Approx. 4

      OK or NG 

      OK: GO TO 2.

      NG: Replace combination meter. Refer to "REMOVAL AND INSTALLATION ".

2. CHECK HARNESS CONNECTOR
   1. Turn ignition switch OFF.
   2. Check combination meter and fuel level sensor unit terminals (meter-side and harness-side) for poor connection.

      OK or NG 

      OK: GO TO 3.

      NG: Repair or replace terminals or connectors.

3. CHECK FUEL LEVEL SENSOR UNIT CIRCUIT
   1. Disconnect combination meter connector and fuel level sensor unit connector.
   2. Check continuity between combination meter harness connector (A) and fuel level sensor unit and fuel pump harness connector (B).
      CONNECTOR TERMINAL CONTINUITY CHART
      
      

      A		B		Continuity
      Connector	Terminal	Connector	Terminal
      M24	8	B48	2	Yes

   3. Check continuity between combination meter harness connector (A) and ground.
      CONNECTOR TERMINAL CONTINUITY CHART
      
      

      A		Ground	Continuity
      Connector	Terminal
      M24	8		No

      Fig 1: Checking Continuity Between Combination Meter Harness Connector And Ground

      Courtesy of NISSAN MOTOR CO., U.S.A.

      OK or NG 

      OK: GO TO 4.

      NG: Repair harness or connector.

4. CHECK FUEL LEVEL SENSOR UNIT GROUND CIRCUIT
   1. Check continuity between combination meter harness connector (A) and fuel level sensor unit and fuel pump harness connector (B).
      CONNECTOR TERMINAL CONTINUITY CHART
      
      

      A		B		Continuity
      Connector	Terminal	Connector	Terminal
      M24	4	B48	5	Yes

   2. Check continuity between combination meter harness connector (A) and ground.
      Fig 2: Checking Continuity Between Combination Meter Harness Connector And Ground

      Courtesy of NISSAN MOTOR CO., U.S.A.
      CONNECTOR TERMINAL CONTINUITY CHART
      
      

      A		Ground	Continuity
      Connector	Terminal
      M24	4		No

      OK or NG 

      OK: GO TO 5.

      NG: Repair harness or connector.

5. CHECK FUEL LEVEL SENSOR UNIT

   Check fuel level sensor unit. Refer to "ELECTRICAL COMPONENT INSPECTION ".

   OK or NG 

   OK: Check fuel level sensor unit installation, and check whether the float arm interferes or binds with any of the internal components in the fuel tank. Repair or replace malfunctioning part, if necessary.

   NG: Replace fuel level sensor unit.