Fuel Level Sensor Signal Inspection

Symptom:

• Fuel gauge indication is malfunction.
• Low-fuel warning lamp indication is irregular.

Fuel level sensor unit

• Depending on vehicle position or driving circumstance, the fuel level in the tank varies, and the pointer may fluctuate.

Low-fuel warning lamp

• Depending on vehicle position or driving circumstance, the fuel in the tank flows and the warning lamp ON timing may change.

1. CHECK UNIFIED METER AND A/C AMP. INPUT SIGNAL
   1. Select "METER/M&A" on CONSULT-III.
   2. Using "FUEL METER" on "Data Monitor", compare the value of "Data Monitor" to the indication of fuel gauge of combination meter.
      DATA MONITOR REFERENCE
      
      

      Fuel gauge pointer	Reference value of Data Monitor [lit.]
      Full	Approx. 74
      Three quarters	Approx. 61
      Half	Approx. 42
      A quarter	Approx. 22
      Empty	Approx. 8

      OK or NG 

      OK: GO TO 2.

      NG: Replace combination meter.

2. CHECK FUEL LEVEL SENSOR
   1. Turn ignition switch OFF.
   2. Check components. Refer to "ELECTRICAL COMPONENT INSPECTION ".

      OK or NG 

      OK: GO TO 3.

      NG: Replace fuel level sensor unit.

3. CHECK FUEL LEVEL SENSOR (SUB) CIRCUIT
   1. Disconnect unified meter and A/C amp. connector and fuel level sensor unit (sub) connector.
   2. Check continuity between unified meter and A/C amp. harness connector (A) and fuel level sensor unit (sub) harness connector (B).
      TERMINAL CONTINUITY REFERENCE
      
      

      A		B		Continuity
      Connector	Terminal	Connector	Terminal
      M65	42	B52	1	Yes

   3. Check continuity between unified meter and A/C amp. harness connector (A) and ground.
      TERMINAL CONTINUITY REFERENCE
      
      

      A		Ground	Continuity
      Connector	Terminal
      M65	42		No

      OK or NG 

      OK: GO TO 4.

      NG: Repair harness or connector.

      Fig 1: Checking Continuity Between Unified Meter And A/C Amp. Harness Connector And Ground

      Courtesy of NISSAN MOTOR CO., U.S.A.
4. CHECK FUEL LEVEL SENSOR (MAIN-SUB) CIRCUIT
   1. Disconnect fuel level sensor unit and fuel pump (main) connector.
   2. Check continuity between fuel level sensor unit (sub) harness connector (A) and fuel level sensor unit and fuel pump (main) harness connector (B).
      TERMINAL CONTINUITY REFERENCE
      
      

      A		B		Continuity
      Connector	Terminal	Connector	Terminal
      B52	2	B433	2	Yes

   3. Check continuity between fuel level sensor unit (sub) harness connector (A) and ground.
      TERMINAL CONTINUITY REFERENCE
      
      

      A		Ground	Continuity
      Connector	Terminal
      B52	2		No

      Fig 2: Checking Continuity Between Fuel Level Sensor Unit (Sub) Harness Connector And Ground

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

      OK or NG 

      OK: GO TO 5.

      NG: Repair harness or connector.

5. CHECK FUEL LEVEL SENSOR (MAIN) CIRCUIT

   Check continuity between fuel level sensor unit and fuel pump (main) harness connector (A) and unified meter and A/C amp. harness connector (B).

   TERMINAL CONTINUITY REFERENCE
   
   

   A		B		Continuity
   Connector	Terminal	Connector	Terminal
   B433	5	M65	58	Yes

   Fig 3: Checking Continuity Between Fuel Level Sensor Unit And Fuel Pump (Main) Harness Connector And Unified Meter

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

   OK or NG 

   OK: GO TO 6.

   NG: Repair harness or connector.

6. CHECK INSTALLATION CONDITION

   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.

   OK or NG 

   OK: Replace unified meter and A/C amp.

   NG: Install the fuel level sensor unit properly.