Why Is My Fuel Gauge Reading Incorrectly?

At its most basic, a fuel gauge is a handy indicator telling you how much gas or diesel you have in your vehicle and how long you can drive until you need more. It’s a car feature we tend to take for granted until we have a broken gas gauge. Have you been there? You filled up a few days ago, have driven each day and the gas gauge is stuck on full? Or what about you just went to the fuel station to fill up and your fuel gauge is reading empty when the tank is full?

Either way, you know your gas gauge is broken. If you are prone to being anxious, not knowing how long you can drive before running out of gas can be stressful. Not only that, repeatedly driving on a very low gas tank can hurt your vehicle’s fuel pump in various ways. A better understanding of the issue can help you decide the best way to solve the issue. Here are four commons reasons why your fuel gauge is not reading correctly.

How to Tell If Your Fuel Gauge Is Broken

1. Fuel Gauge Sender Failure

More commonly known as a fuel sending unit, the component is what sends the fuel level signal to your dashboard indicator. While you are operating your vehicle, the sending unit is constantly in motion. This activity means it is rubbing against the variable resistor. The more you drive your vehicle, the move likely this friction will lead to an open or shorted circuit. When an open circuit occurs, the gas gauge may interpret the change in voltage from the failed sending unit as either full or empty. This is the most common reason why your gas gauge is reading wrong.

2. Circuit Problems

Circuit Problems – The gas gauge circuit is wiring that connects the gas gauge, sending unit, the battery, and a ground. The provides the power from the car to operate the electrical components of the vehicle. Because the gas gauge runs through this circuitry, if there is a problem such as a loose connection or corrosion within the circuit, this can cause an error with the gas gauge reading. If you feel comfortable under the hood, go ahead and check for loose or dirty wiring. Sometimes it’s the smallest thing causing a seemingly big problem. To learn more about circuitry, check out how car electrical systems work.

3. Fuel Gauge Is Faulty

Fuel Gauge is Faulty – This is less likely than the previous two issues. The gas gauge is the visual indicator between the fuel tank and the sending unit. In other words, it’s what you read inside the cabin of your vehicle telling you how much fuel you have. Typically, if there is an issue with the fuel gauge, there is a problem with receiving input from the sender. This could be from a bad ground or once again related to the circuitry. A proper diagnosis can help determine if this is the issue.

4. Instrument Cluster Failure

Instrument Cluster Failure – Instrument cluster is the industry’s way to essentially say dashboard indicators. This includes your fuel gauge, speedometer and so forth. With some luck, this will not be the issue. While it is the least likely cause your fuel gauge is reading incorrectly, it is the most expensive reason. Most newer vehicles have a fully-integrated instrument cluster meaning if one indicator has an issue, the whole unit needs to be replaced to fix the problem. Make sure to check out any warranties associated with your vehicle if this seems to be the problem.


Having a broken gas gauge or anything wrong with your vehicle is no fun. It puts your safety and the integrity of the vehicle in jeopardy. Understanding the root cause of any problem you may be experiencing with your vehicle along with a trusted mechanic or service center can help ease any stress you may experience. If you have any questions about your fuel gauge or any other issue, let us know and we would love to talk about it.

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