Nissan Altima Replace Fuel Level Sensor (FLS) To Fix DTC P0463

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Purpose

This article outlines the procedures to diagnose and confirm Diagnostic Trouble Code (DTC) P0463 on a 2019 Nissan Altima L4, 2.0L and replace the Fuel Level Sensor to resolve the issue.

Introduction

In cases where the Malfunction Indicator Lamp (MIL) on your vehicle’s dashboard is illuminated, and the Engine Control Module (ECM) has stored DTC P0463, it indicates the ECM has detected an incorrect fuel gauge reading (the signal from the fuel tank indicates there is more fuel in the tank than the tank can actually hold). This fault doesn’t make the vehicle difficult to drive, but it can be inconvenient.

The Fuel Level Sensor is housed within the Fuel Level Sensor unit. This sensor's primary function is to detect the fuel level within the fuel tank and transmit a signal to the ECM representing this value. The sensor has two essential components: a mechanical float and a variable resistor. The output voltage of the Fuel Level Sensor changes depending on the position of the mechanical float.

Symptoms of DTC P0463 include:

• Malfunction Indicator Lamp (MIL) ON or flashing
• Running out of gas
• Low fuel warning light
• Untrustworthy fuel gauge

Possible causes of this fault are:

• Faulty Fuel Level Sensor
• Fault in the sensor circuit
• Harness is open or shorted

When DTC P0463 is present on a 2019 Nissan Altima L4 2.0L, replacing the Fuel Level Sensor may resolve the issue.

Diagnostic Procedures

Initial Inspection

During your initial inspection, check for obvious signs of mechanical damage such as torn inlet boots, missing or broken vacuum tees, and/or cracked, broken, or disconnected wire harnesses. Make sure all harness connectors are properly placed and secure in the connectors and holders. Also, check the connectors for corrosion, frayed wiring, and damaged terminals.

In addition, inspect the battery terminals and check the battery state of charge before attempting to diagnose electrical faults. This DTC sets if the PCM detects that the control line is shorted or open. Refer to the Vehicle Emissions Warranty Manual for time and mileage coverage for the emissions-related fault(s). For additional information, refer to the Service Manual or applicable Technical Service Bulletin (TSB).

Diagnostic Procedures

a. Turn the ignition OFF. Disconnect the Fuel Level Sensor (FLS).

b. Turn the ignition to the Key ON Engine OFF (KOEO) position. Use a Digital Multimeter (DMM) to measure the voltage between terminal signal Pin 2 (White) of the FLS harness connector and ground. With the fuel tank FULL, the voltage should be 11V.
- If voltage is not within specification, inspect for short-to-power, short-to-ground or open circuits. Perform Repair Validation.
- If the voltage is within specification, proceed to Step c

c. Check the voltage between Pin 5 (Blue) of the FLS harness connector and ground. The value should be battery voltage.
- If the value is within specification, perform Repair Validation.
- If the value is not within specification, proceed to Step d.

d. Use a DMM to measure the resistance at the FLS connector. Place the leads at Pin 2 (White) and Pin 3 (Green).
Specification:
Gauge Full (Full fuel tank): 51 Ohms.
Gauge End (Empty fuel tank): 300 Ohms.
- If the value is not within specification, replace the FLS. Perform Repair Validation.
- If the value is within specification, replace the Engine Control Module (ECM). Perform Repair Validation.

Replace the Fuel Level Sensor

Cautions: To prevent injury, wear a facial mask that is resistant to pressurized flammable fuel when performing this procedure.

Removal

Step 1 – Release the fuel pressure from the fuel lines.

Step 2 – Open the fuel filler cap and release fuel pressure inside the fuel tank.

Step 3 – Disconnect the negative battery cable.

Step 4 – Remove the rear seat cushion assembly.

Step 5 – Turn the four retainers to disengage clips.

Step 6 – Remove the Fuel Level Sensor unit and fuel pump.

Step 7 – Disconnect the harness connector from the Fuel Level Sensor.

Step 8 – Release tab (1), and slide the sensor unit and float arm up.

Installation

Installation is accomplished in the reverse order of removal.

NOTE: Always replace O-ring and clamps with new parts.

Repair Validation: 

• Erase DTC(s) and Freeze Frame (FF) data. 
• Perform the KOEO and Key ON Engine RUNNING (KOER) test or perform the drive cycle requirements for the fault area.
• Optionally, operate the vehicle within the conditions recorded in the Freeze Frame data when DTC P0463 was initially set.
• Check for pending or stored DTCs. If none are found, the repair is complete.

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