P0463: Fuel Level Sensor Circuit High Input

What is P0463?

P0463 is a generic OBD-II diagnostic trouble code (DTC) defined as “Fuel Level Sensor Circuit High Input.” 

Your vehicle’s powertrain control module (PCM) or Engine Control Module (ECM) monitors the fuel level circuit to determine the amount of gas in the fuel tank and manage fuel usage and economy.

The P0463 code indicates that your vehicle’s fuel level sensor unit is sending unusually high fuel level readings to the PCM. As a result, the fuel gauge doesn’t display accurate fuel levels in the gas tank. 

The fuel level sensor (also called a fuel sending unit or fuel level sender) utilizes a mechanical float in the fuel tank that’s attached to an arm. The arm is grounded via the fuel tank or a dedicated ground circuit. As the arm raises or lowers based on the fuel level, the sensor resistance to ground changes, varying the signal voltage. 

The signal voltage of your fuel sending unit is typically 5 volts, though that value may vary based on make and model. If the fuel level signal to the powertrain control module is over 5 volts for a designated amount of time, it will set the DTC P0463, and the Check Engine Light turns on. 

Note: The fuel level sensor is often built directly into the fuel pump assembly. While there are exceptions, usually, you can’t replace one without replacing the other. 

Some related codes to P0463 include DTC P0462, P0461, and P0460.

Common symptoms

Code P0463 doesn’t exhibit many symptoms. Here are the most obvious ones are:

• An illuminated Check Engine Light
• Inaccurate or fluctuating fuel gauge readings (this happens when the fuel level indicated by the fuel sender is different from the actual fuel level)
• Activated Low Fuel Light or the Low Fuel alarm sounds

The engine dies and won’t restart because the vehicle is out of fuel, though the fuel gauge indicates a full tank

Can I still drive?

Code P0463 won’t affect your vehicle performance or driving experience. 

However, it could become a serious inconvenience because your fuel level gauge won’t display the correct amount of fuel in your gas tank, and you won’t know when to fill it up. As such, if your vehicle runs out of fuel in heavy traffic, the situation could become dangerous. 

Also, if you need an OBD-II emissions test to renew your vehicle’s registration, the P0463 code will keep the Check Engine Light lit. Your car won’t pass an emissions test until the Check Engine Light issue is resolved. So, it’s still important to get this code fixed ASAP.

P0463 causes

While symptoms for code P0463 are few, many more causes can account for the problem. 

Here are some of the more common ones:

• Damaged fuel tank
• Defective wiring or harness connector to the fuel sensor 
• A malfunctioning fuel sensor 
• The fuel level sensor circuit is shorted or open
• The ground signal circuit is open or has high resistance
• The sending unit arm is mechanically damaged
• A faulty fuel pump module
• Defective PCM or ECM (rare)

Most of the time, the P0463 code results from a damaged fuel tank or faulty wiring around the fuel sender.

Diagnosis

The diagnostic process for DTC P0463 is relatively straightforward but still requires detailed attention to avoid unnecessary repairs or replacements. 

Here’s an overview of the steps a professional technician would take:

1. Using an OBD-II scan tool, check if additional codes are present in the system. Use the scan tool to clear the codes from the system, along with the Check Engine Light, and test drive the vehicle to see if the P0463 code returns.
2. Go through the freeze frame and gas gauge data with the OBD-II scan tool. Assess how much the fuel level readings vary from the actual fuel level. 
3. Add additional fuel into the tank to check if the fuel level gauge reading varies accordingly. 
4. Check the wiring and connections around the fuel level sensor and harness. The issue might be a connector or wiring instead of the sensor.
5. Check the fuel tank exterior for signs of impact. Road hazards can damage the fuel tank,  and the fuel pump or fuel level sender along with it. Also, make sure the ground strap isn’t missing or corroded. 
6. Check the ground circuit for shorts, opens, or high resistance with a digital multimeter. 
7. If code P0463 persists, the fuel level sensor or the entire fuel pump may need replacement. Replacing the fuel level sensor unit can be difficult because the gas tank (on many vehicles) needs to be removed to access it.

A common mistake is prematurely replacing the fuel pump when the real problem is a faulty gas gauge, damaged connector, or wiring.

Possible repairs for P0463 & Costs

Engine code P0463 has many causes, so there isn’t a single fix to the problem. The most important thing is first to pinpoint the root cause. 

Some of the more common repairs for the P0463 engine code include:

• Fuel tank repair or replacement
• Fuel level sensor float repair or replacement
• Fuel level sensor repair or replacement
• Fuel pump repair or replacement
• Fuel level sensor wiring harness replacement
• Securing loose connection in the fuel level sensor circuit

Most auto shops will start with an hour of diagnosis time, which typically costs between $75-$150. After that, here are some of the estimated costs of replacements, including parts and labor: 

• Fuel tank: $1,291 and $1,441 
• Fuel level sensor: $896 and $1,051 
• Fuel pump: $806 to $967