Fuel Level Sensor Signal Inspection

Symptom:

• Fuel gauge indication is malfunction.
• Low-fuel warning lamp indication is irregular.
  NOTE: The following symptoms are not malfunction.

Fuel level sensor unit

• Depending on vehicle position or driving circumstance, the fuel level in the tank varies, and the pointer may fluctuate.
• If the vehicle is fueled with the ignition switch ON, the pointer will move slowly.

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 A/C AMP" 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.
      REFERENCE VALUE OF DATA MONITOR
      
      

      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 "CHECK FUEL LEVEL SENSOR UNIT ".

   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).
      CONTINUITY SPECIFICATIONS
      
      

      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.
      CONTINUITY SPECIFICATIONS
      
      

      A		Ground	Continuity
      Connector	Terminal
      M65	42		No

      Fig 1: Checking Continuity Between Unified Meter And A/C Amp. 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 (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).
      CONTINUITY SPECIFICATIONS
      
      

      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.
      CONTINUITY SPECIFICATIONS
      
      

      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).

   CONTINUITY SPECIFICATIONS
   
   

   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.