P0463 on 2016-2022 Infiniti Q50: Fuel Level Sensor Circuit High Input Fixes

What's Unique About the 2016-2022 Infiniti Q50

For the 2016-2022 Infiniti Q50, this code is directly addressed by a manufacturer Technical Service Bulletin (TSB). The key takeaway from TSB ITB22-015 is that the fuel level sensor is a known issue and, importantly, can be replaced as a separate component. This is a significant advantage because the Q50 uses a saddle-style fuel tank that straddles the driveshaft, requiring two separate fuel level sending units (a primary and a sub-level sensor). On many other vehicles, a faulty sensor requires replacing the entire, much more expensive, fuel pump assembly. Infiniti explicitly warns against this unnecessary cost for this code.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle. 👇

Symptoms You May Notice

• Check Engine Light is on
• Fuel gauge is inaccurate (e.g., stuck on empty, stuck on full, or erratic)
• Fuel gauge reads empty immediately after filling the tank.
• Low fuel light may be on constantly, even with a full tank.
• In rare cases, the gauge may not register a small amount of added fuel, but will slowly creep up to the correct level after several minutes of driving.

Most Likely Causes

1. Faulty Fuel Level Sensor (Sending Unit) 🔴 High Probability → Shop Fuel Tank Sending Unit This is a known issue acknowledged by Infiniti in Technical Service Bulletin ITB22-015. The Q50 has two sensors due to its saddle tank design. The internal resistor or the float arm mechanism can fail, leading to an open circuit and the high voltage signal. 🎬 Watch: Understanding the causes and fixes for the P0463 code It's common for one to fail, but many owners and mechanics recommend replacing both at the same time to avoid a second repair job in the near future.
   How to confirm: Test the sensor's resistance with a multimeter while moving the float arm; the resistance should change smoothly. An open circuit or infinite resistance indicates a failed sensor. Access to the sensors is under the rear seat cushions, one on the driver's side (main pump assembly) and one on the passenger's side (sub-level sensor).
   Typical fix: Replace the faulty fuel level sensor(s). The sensors are available separately from the fuel pump. The driver's side sensor is part of the main fuel pump module, while the passenger side sensor is a standalone unit. Both can be accessed via panels under the rear seat.
   Est. part cost: $150-$300 per sensor
2. Wiring or Connector Issue 🟡 Medium Probability The connectors for the fuel level sensors are located under the rear seat. While not a widespread issue, it's possible for these connectors to become corroded or for the pins to become loose, especially if liquid has been spilled in the back seat area. 🎬 See this guide on fixing common Nissan and Infiniti fuel gauge issues
   How to confirm: Visually inspect the wiring harness and connector at the top of the fuel tank access panels under the rear seat for any signs of corrosion, damage, or loose pins. A high input code can be caused by a short to power or a poor ground connection.
   Typical fix: Repair the damaged section of the wiring harness or clean/replace the connector.
   Est. part cost: $10-$50

Rare But Worth Checking

• Instrument Cluster or BCM Fault: → Shop Instrument Cluster The fuel level signal is processed by the combination meter (instrument cluster) before being sent to the ECM. While rare, a fault in the cluster's circuitry could theoretically cause this code. This should only be considered after sensors and wiring have been ruled out.
• Powertrain Control Module (PCM) Fault: This is extremely rare. The PCM is the last component to suspect after all other possibilities, including wiring and the sensor itself, have been thoroughly ruled out.

Diagnosis Steps

1. Verify the code with an OBD-II scanner.
2. Check for any other related fuel system codes (P0460, P0461, P0462).
3. Observe the fuel level reading in the live data stream on the scanner. Does it show an abnormal reading (e.g., 100% or 0%) that doesn't match the actual fuel level?
4. Remove the rear seat bottom cushion to access the two fuel tank service covers.
5. Inspect the wiring and connectors on both the driver's side (main pump) and passenger's side (sub-sensor) access panels. Look for any corrosion, bent pins, or damage.
6. Using a multimeter and a wiring diagram, check for proper voltage and ground at the fuel level sensor connectors.
7. If wiring is confirmed to be good, the next step is to test the fuel level sensors. This requires removing the lock rings and lifting the units out of the tank. Be prepared for fuel fumes.
8. Measure the resistance of each sensor while manually moving the float arm. The resistance should change smoothly through its range of motion. An open circuit (infinite resistance) or a jumpy reading confirms the sensor is bad.

Parts You'll Likely Need

• Fuel Level Sensor (Main/Driver Side) (OEM #25060-4HK0A) — This is the primary sensor and a common failure point for code P0463 on this vehicle, as confirmed by owner experiences and an Infiniti TSB.
  Trusted brands: Genuine Infiniti, Hitachi, Delphi
  OEM price range: $170-$240
  Aftermarket price range: $140-$200
• Fuel Level Sensor (Sub/Passenger Side) (OEM #25060-4HK1A) — The Q50 has a second sensor on the passenger side for the saddle tank. It is often recommended to replace both sensors at the same time to prevent future failures.
  Trusted brands: Genuine Infiniti, Hitachi, Dorman
  OEM price range: $160-$230
  Aftermarket price range: $120-$180
• Fuel Tank O-Ring / Gasket (OEM #Included with sensor or 4F0-919-133-B (example)) — The large O-ring that seals the sensor/pump assembly to the tank should always be replaced whenever the unit is removed to prevent fuel leaks and vapor smells.
  Trusted brands: Genuine Infiniti
  OEM price range: $20-$40
  Aftermarket price range: $10-$25

Related Codes That Often Appear With This One

• P0462 — This code is for 'Fuel Level Sensor Circuit Low Input.' Seeing it alongside P0463 can indicate an intermittent or erratic sensor that is shorting and opening.
• P0461 — This code indicates 'Fuel Level Sensor Circuit Range/Performance.' It often appears when the sensor's signal is unstable or not changing as expected, which can happen as the sensor begins to fail.
• P0460 — A generic fuel level sensor circuit malfunction code. All these codes are mentioned together in TSB ITB22-015 as being related to the same sensor issue.

Technical Service Bulletins (TSBs) & Recalls

• ITB22-015: Published April 5, 2022. Addresses fuel gauge inaccuracy with DTCs P0460, P0461, P0462, or P0463. It explicitly states to replace the fuel level sensor separately and warns that warranty claims for replacing the entire fuel pump assembly for this issue will be charged back.

Platform-Specific Known Issues

• Infiniti has issued Technical Service Bulletin ITB22-015, which directly addresses P0463 and other related fuel level codes. The bulletin confirms the fuel level sensor can be replaced separately, advising against unnecessary replacement of the entire fuel pump module for this specific issue.
• The Q50 platform uses a saddle-style fuel tank to accommodate the driveshaft, which necessitates two fuel level sensors. One is integrated with the main fuel pump on the driver's side, and a secondary 'sub-level' sensor is on the passenger's side. Failure of either sensor can trigger fuel gauge problems.

Mechanic-Grade Diagnostic Values

• Fuel Level Sensor Circuit Voltage — expected: Below 5 Volts. Failure: A sustained reading at or near 5 Volts, which indicates an open circuit or maximum resistance.
• Fuel Level Sensor Resistance — expected: A smooth, continuous change in resistance (Ohms) when moving the float arm from empty to full.. Failure: An infinite resistance reading (Open Loop/OL) or a reading that does not change when the float arm is moved.
• Low-Pressure Fuel System Pressure (at fuel rail) — expected: Approximately 51 psi for the VQ37 engine, which is similar for the VR30.. Failure: Pressure significantly below specification (Note: This tests the fuel pump, not the level sensor, but is a related diagnostic value).

Hidden / Shadow Codes Worth Checking

• U1000 / U1001: These are CAN Communication Line error codes. If either of these codes is present along with P0463, it indicates a potential network communication problem. (see via Standard OBD-II scanner. The service manual advises diagnosing and fixing U-codes first, as a communication failure can cause false sensor codes like P0463.)

Scan Tool Commands That Help

• Infiniti CONSULT / High-End Scan Tool: Data Monitor for Fuel Level Sensor — Use this to observe the live voltage or resistance value being reported by the fuel level sensor. This helps determine if the value is fixed high (indicating an open circuit) without needing to immediately access the sensor itself.
• Infiniti CONSULT / High-End Scan Tool: Instrument Cluster Self-Test / Actuator Test — This command sweeps all the gauges (including fuel) through their full range of motion. If the fuel gauge fails to sweep correctly during this test, it points towards a fault within the instrument cluster itself, rather than the sensor or wiring.

Wiring & Ground Locations

• Fuel Level Sensor Units — Top of the fuel tank, accessible by removing the rear seat bottom cushion. The main unit is on the driver's side, and the sub-unit is on the passenger's side.. This is the location of the sensors and their primary electrical connectors, a common point of failure.
• Combination Meter (Instrument Cluster) — In the dashboard, behind the steering wheel.. The fuel level sensor signal is sent here first for processing before being relayed to the ECM via CAN bus. A fault in the meter's circuitry can cause P0463.
• Unified Meter and A/C Amplifier — Part of the instrument cluster/center display assembly.. This is the specific control unit that interprets the sensor's resistance reading. On related platforms, it is a known failure point when new sensors do not fix the issue.
• Fuel Pump Control Module — In the left rear of the luggage compartment (trunk).. While less likely to cause a sensor-specific code, knowing its location is important for comprehensive fuel system electrical diagnosis.
• Fuel System Ground — A ground distribution diagram indicates the 'fuel level sensor unit & fuel pump (main) shield' is a grounded component.. A poor ground connection for the sensor circuit can cause incorrect voltage readings, leading to a P0463 code.

Real Owner Repair Stories

• Reddit user in r/q50 (Infiniti Q50 (year not specified)) — Fuel gauge did not work correctly.
  ❌ Tried (didn't work) Not specified, but implies other common fixes were considered.
  ✅ What actually fixed it Replacement of the entire instrument cluster.
• YouTube creator 'Kots G37' (Infiniti G37 (similar platform and known issue)) — Fuel gauge read half full when the tank was actually empty, causing the car to run out of gas. P0463 was present.
  ❌ Tried (didn't work) Replacing the driver's side (secondary) fuel level sensor., Replacing the passenger side (primary) fuel level sensor with the fuel pump.
  ✅ What actually fixed it The issue was not resolved by replacing both sensors, leading to the conclusion that the next step is to replace the 'AC amp module unit' (Unified Meter and A/C Amp), a known but rare failure point that processes the gauge signal.

When the Usual Fixes Don't Work

• While the overwhelming majority of P0463 cases on the Q50 are fixed by replacing one or both fuel level sensors as per TSB ITB22-015, there are documented instances where this does not solve the problem. In these cases, the fault was traced back to the dashboard, requiring the replacement of the entire instrument cluster or the specific 'Unified Meter & A/C Amplifier' that processes the gauge signal. This demonstrates that if a sensor replacement fails to fix the code, the diagnostic path must shift from the fuel tank to the instrument panel electronics.

Model Year Variations Within This Range

• 2016-2022: While the primary part numbers for the 3.0t engine (25060-4HK0A and 25060-4HK1A) appear consistent, other engine options like the 2.0t may use different part numbers. For example, part numbers like 25060-6HA0A and 25060-4HL0A/1A also exist for the Q50. It is critical to verify the correct part number by VIN before ordering.
• 2016: Some parts databases show a production note of 'From 09/2016' for the sub-level sensor (25060-4HK1A), which may indicate a running change during the 2016 model year. While this may not affect compatibility for most 2016 vehicles, it's a detail to be aware of for very early production models.