This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.
Fuel Level Sensor Circuit High Input
This is a fairly cut-and-dried trouble code that doesn’t require extended explanation. Your vehicle’s Power Control Module (PCM) measures the remaining fuel in your gas tank from the low voltage signals sent by the fuel level sensor. A typical sensor reading should be no higher than 5volts, so any voltage reading outside the manufacturer specified range causes the PCM to save a P0463 code.
Like most sensor trouble codes, there are only a few explanations for the system to save a trouble code. Here are the most common issues that can cause a P0463.
- A problem with the fuel level sensor circuit (specifically the wiring and connectors)
- A faulty fuel level sensor (it can happen over time, but don’t assume this is the reason)
- Damage to the fuel level sensor float in the gas tank (this means having a professional drain and drop your gas tank to check for damage)
- Damage to, or corrosion in the gas tank (another drain and drop fix)
- A problem with the PCM (rare, as PCMs have a significant amount of electrical and physical protection from damage)
Here are the symptoms most people notice first that would indicate a P0463 code is the culprit:
- Illumination of the Check Engine Light (the PCM has detected an out of range voltage reading from the fuel level sensor)
- A fluctuating or inaccurate fuel gauge (It may be off by a quarter tank or read empty even after a fill up)
- Illumination of the Fuel Light and/or sounding of the alarm for low fuel (this is how most people discover they have a problem if the check engine light doesn’t go on first)
The first part of this troubleshooting process can easily be done by a competent DIY mechanic if you have an OBDII scanner and a basic knowledge of locating parts on an automobile. The second part of the process involving the inspection of the fuel tank may require professional equipment and training that most DIY mechanics are unlikely to have access to on their own. Here are the troubleshooting steps to follow for diagnosing the cause of a P0463 code:
- First, a mechanic will first verify if the P0463 is present and record any other OBDII codes stored by the vehicle’s computer.
- Next, they’ll clear all codes and attempt to recreate the scenario that may have caused the code to save the first time.
- During this test, the mechanic will need to keep an eye on the fuel gauge and the real time data displayed on the OBDII scanner. Fluctuations in voltage outside the manufacturer specs will help them determine if the fuel sensor is showing too much or too little fuel in the tank, and may help determine if the problem is physical or electrical.
- Finally, the mechanic will start checking on the probable causes of a P0463 starting with a close inspection of the wiring harness and fuel tank sensor. If they’ve checked the wiring and sensor for damage and all the connectors are tight, it may be necessary to remove the gas tank for inspection.
- Draining, removing and inspecting a vehicle fuel tank is best undertaken by professionals, so if you’ve tried fixing the wiring or replacing the sensor already, it may be time to make an appointment with your local repair shop to see if there are other reasons the P0463 continues to display on your OBDII scanner.
It’s important to follow the troubleshooting steps for this code closely, otherwise you may replace perfectly good parts without fixing the issue. Here some common errors many DIY mechanics and trained technicians often make with this process:
- Replacing the fuel pump when the problem is actually a damaged or faulty fuel gauge or fuel level sensor.
- Replacing larger, more expensive components before inspecting wiring and connectors for faults or shorts. (ALWAYS check the wiring before replacing a part)
- Replacing the fuel gauge when the problem is a corroded or otherwise damaged wire or connector.
How serious is this?
Your vehicle isn’t in any danger of suddenly exploding from this particular issue, but you may unexpectedly run out of gas or see your fuel light on when you still have plenty of gas in the tank. Getting stuck by the side of the highway in the winter or a summer thunderstorm isn’t fun, and without the ability to tell how much fuel is left in the tank can leave you in a real pickle. Moreover, running out of gas in rush hour city traffic can result in an accident. Bottom line, if your check engine light is on, get your vehicle checked out.
What repairs can fix the code?
Here are some of the repairs that may be needed to correct/eliminate a P0463:
- Repairing or replacing the fuel tank (labor intensive and expensive)
- Repairing or replacing the fuel level sensor float (labor intensive, but not particularly expensive)
- Repairing or replacing the fuel level sensor (may or may not be expensive depending on the vehicle and how easy it is to access the sensor)
- Replacing the wiring harness for the fuel level sensor (fairly simple and inexpensive)
- Tightening a loose connection in the fuel level sensor circuit (simple and free)
Your Check Engine Light exists for a reason. As soon as you see it, you should verify what codes are present with an OBDII scanner. If you can’t do that yourself, you can take it into a repair shop where they can diagnose the issue for you. Coding a P0463 won’t make your vehicle undrivable, but you do run a high risk of running out of gas unexpectedly. Pull the codes with your own scanner if you can, and check the wiring and connectors to the fuel level sensor first if you see a P0463. Otherwise, professional diagnosis and repair is highly recommended.