P0463 – Fuel tank level sensor -high input – TroubleCodes.net (2024)

P0463 – Fuel tank level sensor -high input – TroubleCodes.net (1)

By Reinier (Contact Me)
Last Updated 2016-08-17
Automobile Repair Shop Owner

CodeFault LocationProbable Cause
P0463 Fuel tank level sensor -high input
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Wiring short to positive, fuel tank level sensor, ECM

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Table of Contents

  1. What Does Code P0463 Mean?
  2. What are the common causes of code P0463 ?
  3. What are the symptoms of code P0463 ?
  4. How do you troubleshoot code P0463 ?
  5. Codes Related to P0463
  6. Get Help with P0463

What Does Code P0463 Mean?

OBD II fault code P0463 is defined as “Fuel Level Sensor Circuit High Input”, and is set when the PCM (Powertrain Control Module) or BCM (Body Control Module on some applications) detects a signal from the fuel level sender unit that indicates a fuel level that exceeds the fuel tank’s capacity.

The PCM or BCM does not “know” how much fuel is in the fuel tank: the only information the controller has about the fuel level derives from the signal voltage generated by the sender unit. Therefore, regardless of whether the tank is full or empty, the controller expects to see a predefined signal voltage that corresponds to that state, which means that if say, a short circuit (or any other problem) creates a resistance that is inconsistent with either state, the controller will set code P0463 and illuminate a warning light.

Put in another way, if the sender unit’s input circuit is fully functional, code P0463 will typically not be set when a mechanical problem prevents movement of the float arm. All that will happen in this case is that the fuel gauge reading will not reflect changes in the actual fuel level in the tank.

In terms of operation, fuel level sender units use variable resistors to indicate the actual fuel level in the tank. In practical terms, this is accomplished by means of a float that is attached to a moveable arm, the other end of which is in contact with a variable resistor. As the fuel level changes, the movable arm either rises or drops, which brings the contact point of the arm into contact with different parts of the variable resistor.

Thus, when the tank is empty, the resistor will generate the minimum reference voltage for that application because there is more resistant material for the current to pass through, which results in a lower voltage reaching the fuel gauge, giving an “Empty” reading. Conversely, when the tank is full, the resistance decreases, resulting in close to the maximum signal voltage being sent to the fuel gauge, thus producing a “Full” reading.

While the basic operating principles of fuel level sender units are much the same across all manufacturers, there are two notable exceptions to this rule. Ford and GM generally switch the electrical resistance around, meaning that on these makes the maximum signal voltage is generated when the tank is empty and vice versa: the minimum signal voltage is generated when the tank is full.

The image below shows the typical construction of a fuel pump canister. Note the fuel level sender unit that forms part of the canister. Be aware that not all level sender units are incorporated into the pump canister; on some applications the sender unit is mounted separately.


Circuit High Input codes are mostly caused by defective alternators that develop excessive voltages, although there may be other causes as well, such as short circuits that “leak” current into a particular system from other, unrelated systems that work on higher voltages. Note that in the case of short circuits that leak power into a control circuit, there is likely to be other, seemingly unrelated trouble codes present along with the code(s) being investigated. Diagnosing a “high input” code will always involve a thorough testing of the charging system as a first step, followed by measures to isolate the system from all other possible sources of power during resistance, continuity, and reference voltage tests.

What are the common causes of code P0463 ?

Typical causes of code P0463 are much the same across all applications, and these could include the following-

  • Burnt, damaged, shorted, or corroded wiring and/or connectors.
  • Open circuits.
  • Loss of ground.
  • Defective fuel level sender unit.
  • Damage to the fuel tank that inhibits the free movement of the moveable arm. Note that not all applications will set the code if damage to the fuel tank occurs.
  • Defective PCM/BCM. Note that this is a rare event, and the fault must be sought elsewhere before any controller is replaced.

NOTE: On some Ford products, fuel with high sulphur content can cause the build-up of a type of varnish on the variable resistor, which build-up prevents contact between the resistor and the moveable contact, thus setting code P0463. While some aftermarket fuel additives might assist in removing the varnish deposit, the better option is to replace the fuel level sensor unit.

What are the symptoms of code P0463 ?

Apart from a stored trouble code and an illuminated warning light, the symptoms of code P0463 typically include the following-

  • Indicated fuel level may be different from the actual level.
  • Low fuel level warning light may flash, or be illuminated permanently despite there being sufficient fuel in the tank not to trigger the low level warning.
  • Engine may shut off or not start due to lack of fuel, despite the fuel gauge registering readings above “Empty”.
  • In some cases, the self diagnostic system may display “EVAP System Not Ready” messages when it cannot register an accurate fuel level.

How do you troubleshoot code P0463 ?

NOTE #1: Before attempting a diagnosis of code P0463, consult the manual on the type of sender unit the application is fitted with. Most new applications are fitted with magnetic fuel gauges that depend on a varying magnetic field to deflect the indicating needle. Although the basic operating principle remains the same on these systems, i.e., a variable resistance that varies the gauge input voltage, the resistances involved are generally much higher than those found on other designs.

In addition, almost all magnetic fuel gauges follow the example set by GM: the lower the fuel level, the lower the resistance, and vice versa. Also be aware that the fast response time seen on a magnetic fuel gauge is a function of its design, and it does not indicate a short circuit as it sometimes would on a purely resistance-type gauge.

NOTE #2: Always refer to the manual for the application being worked on for the correct resistance values, because while the typical signal voltage across all manufacturers is around 5 volts, the electrical resistance that produces “Empty” or “Full” readings on the fuel gauge varies considerably between applications.

NOTE #3: Code P0463 specifically refers to issues in the fuel level sender unit input circuit, even though incorrect or erratic fuel gauge readings can also be caused by short circuits and other problems between the sender unit and the fuel gauge.

NOTE #4: When diagnosing code P0463, make sure that the fuel tank holds between 25%, and 75% of its capacity, since the self diagnostic program on most applications requires specific amounts of fuel to be in the tank before self diagnostic tests can be completed. Trying to diagnose this code with a low (or too high) fuel level can lead to misdiagnoses and hours of wasted time.

Record all codes present, as well as all available freeze frame data. This information can be useful should an intermittent fault be diagnosed later on.

Consult the manual on the location, function, color-coding, and routing of all wiring and fuses associated with the fuel sender unit, and perform a thorough visual inspection of all wiring. Look for damaged, burnt, disconnected, shorted, and corroded wiring, connectors, and fuses. Make repairs as required, clear all codes, and retest the system to see if the code returns.

NOTE #1: In some cases it may be necessary to remove the fuel tank from the vehicle to gain access to all wiring. Removing the tank is considerably easier with the vehicle on a hoist or vehicle lift: however, if a lift is not available, ALWAYS use properly rated jack stands to support the vehicle while removing the tank. Moreover, always observe basic safety rules, and NEVER smoke while working on a vehicle’s fuel system.

NOTE #2: When removing a fuel tank, always make notes, or take pictures of the routing and location of all wiring, fuel/vacuum lines, and other components. It is very easy to pinch wiring or fuel/vacuum lines during reassembly, which could lead to the fuel/EVAP system not working. It also goes without saying that all connections of hoses and lines must be made to industry standards during reassembly to avoid the possibility of leaks or other issues.

If no visible damage to wiring and/or connectors is found perform resistance, continuity, ground, and reference voltage tests on all associated wiring, but be sure to disconnect the fuel level sender unit from the PCM/BCM to prevent damage to the controller. Compare all obtained readings to those stated in the manual, but pay particular attention to the ground wire(s) and connection(s), since the sender unit relies on a sound ground to work at all.

Test the sender units’ ground by comparing it to a voltage drop test between the battery positive terminal and a suitable ground on the vehicle frame. The difference between the two voltage drop tests should not be greater than about 100 millivolts. Greater values indicate a malfunction in the input circuit. Make repairs or replace wiring as required to ensure that all readings fall within specifications, clear all codes, and retest the system to see if the code returns.

If the code persists despite all electrical values falling within specifications, test the sender unit itself by unplugging it from the system where it connects to the wiring harness. Depending on the application, the indicating needle on the gauge will move to either the “Full” or the “Empty” position. Note that the needle will move past either point, or to built-in stops in the gauge, thus, as far as it can go.

If the gauge needle does this, both the sender unit and associated wiring are fully functional. Note however that on some applications the needle may move rather slowly, so allow enough time for the needle to reach its point of maximum deflection before drawing any conclusions from this test.

If unplugging the sender unit does not produce maximum needle deflection, and it is certain that all electrical values fall within specifications it is safe to assume that the sender unit is defective. Be aware though that replacing the fuel level sender unit is more difficult on some applications than on others- in some cases, special tools may be required to remove the locking ring that secures the fuel pump canister. Always consult the manual on the correct (and safest) procedure to remove the fuel tank, or on how to gain access to the sender unit by removing seats and other items such as carpets.

Note that fuel sender units can typically not be repaired, but to avoid compatibility issues with the application’s electrical system, only ever replace a sender unit with an OEM part. While an aftermarket sender unit may fit the application, it often happens that the resistance rating of an aftermarket unit does not match the specifications of the application it is fitted to, which could result in inaccurate fuel level readings, or even fuel level readings that could indicate the tank is full when it is in fact empty.

WARNING: It is very important to take extreme care when fitting a fuel level sender unit. Any damage to the movable arm, for instance, barely noticeable bending or deformation of the arm could cause wildly inaccurate fuel level readings.

If the code persists despite having completed the repair procedure outlined above, it is likely that an intermittent fault is present. Be aware though that intermittent faults can often be extremely challenging and time consuming to find and repair, and in extreme cases the fault may have to be allowed to worsen considerably before an accurate diagnosis and definitive repair can be made.

  • P0460Relates toFuel Level Sensor Circuit Malfunction”
  • P0461Relates toFuel Level Sensor Circuit Range/Performance”
  • P0462Relates toFuel level Sensor Circuit Low Input”
  • P0464Relates toFuel level Sensor Circuit Intermittent”

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P0463  – Fuel tank level sensor -high input – TroubleCodes.net (2024)


What can cause a P0463 code? ›

Causes. Any part of the circuit from your fuel level sensor to your powertrain control module could be the culprit. A short in the wiring is the most common cause, so your first step should be to inspect the entire system for any sign of a short.

What is a common cause of fuel level sensor failures? ›

Circuit Problems

Another reason why the fuel level sensor may fail is because it is not getting the amount of voltage it needs to function properly. In order for an accurate reading to go from the fuel level sensor to the fuel gauge, there needs to be a current flowing between them.

What is the code for the fuel level sensor? ›

The P0463 code involves your car's fuel level sensor. One of your car's computers (usually the powertrain control module or PCM) will set the code when the fuel level sensor's signal is too high.

How do I reset my fuel sensor? ›

Reseting a Digital Fuel Gauge

Turn on the car and push the "Trip/Odo" button to put the odometer into "ODO" mode. Turn the car off, then press and hold the "Trip/Odo" button and turn the car back on. Press and release the button 3 times, holding it down for 4 to 5 seconds the third time.

What causes a fuel tank pressure sensor to go bad? ›

Common reasons for failure:

Overexposure to extreme temperatures, weather, vibration, and/or corrosive fuel vapors. Over filling the fuel tank will cause fuel to overflow into the charcoal canister and other overflow lines can cause the sensor to fail.

What are the 3 common causes of sensor failure? ›

Sensor failures can be caused by mechanical damage, environmental factors, electrical interference, or calibration errors. These failures can have various effects on the PLC system, such as false readings, loss of communication, or system shutdown.

Can you still drive with a bad fuel level sensor? ›

A fuel gauge not working may not make a vehicle undrivable, but not knowing the fuel level risks the vehicle running out of fuel. While walking to the gas station to get fuel is not ideal, running out of gas is not good for the car either. A fuel pump relies on fuel passing through for lubrication and cooling.

What happens when a fuel sensor goes bad? ›

The FTP sensor is used by the ECM to adjust the air/fuel mixture and ignition timing. A malfunctioning FTP sensor can cause the engine to run improperly, leading to rough idling. This symptom is often accompanied by a noticeable vibration or shaking sensation in the cabin of the vehicle.

Can a fuel level sensor go bad? ›

Inaccurate readings from a faulty or failing sender unit can lead to misleading information about your remaining fuel levels. This can result in unnecessary pit stops for refueling or being caught off guard with an empty tank.

How much does it cost to replace a fuel level sensor? ›

Parts alone can cost anywhere between $20 and $270, according to your vehicle's year, make, and model. Part cost can also change if you're buying an individual piece, set, or kit. Labor cost will depend on your location and extent of work required. It can range from $80 to $250.

Will a fuel level sensor make a check engine light come on? ›

The light is on most likely due to the fuel level sensor. The fuel level sensor will cause a p0463 code and will not harm anything. Most auto parts stores will read the code for you for free. As long as the engine light does not flash wile you are driving, you should be safe to drive.

What is the fuel level sensor in the fuel tank? ›

What Are Fuel Level Sensors? Fuel sensors or fuel level indicators are ingenious devices installed inside the fuel tank to measure the accurate fuel level in real time. The data is shared with telematics software such as TrackoBit which massage the raw data and present the users in a digestible format.

What can damage fuel sensor? ›

Wiring Problems: Faulty wiring connections or damaged wiring can disrupt the communication between the fuel gauge and the fuel sensors, leading to erratic readings.

What causes a bad fuel pressure sensor? ›

Wear and Tear: Like many automotive components, fuel pressure sensors can wear out over time due to normal usage and exposure to various elements. The internal components, such as the sensing element and electronic circuitry, may degrade, leading to inaccurate readings or sensor failure.

What causes fuel gauge malfunction? ›

The most common cause of an inaccurate or non-functioning gas gauge is a component called the sending unit. When you're driving, the sending unit rubs against a variable resistor. This can lead to wear over the life of your vehicle.

Can you drive with a bad fuel level sensor? ›

A fuel gauge not working may not make a vehicle undrivable, but not knowing the fuel level risks the vehicle running out of fuel. While walking to the gas station to get fuel is not ideal, running out of gas is not good for the car either.


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