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Summary
  • A stuck fuel gauge can be caused by a faulty fuel sending unit, a blown fuse, or damaged wiring. Sometimes, the fuel gauge might be the problem.
  • To fix a gas gauge stuck on full, try performing an instrument cluster self-test, testing the fuel sending unit, or checking the gauge’s wiring.
  • Located on your dashboard, a fuel gauge informs you how much fuel is left in your tank.

A gas gauge stuck on full might not seem like a pressing issue now, but do you really want to wait until your tank becomes empty, leaving you stranded during a busy day? Without a functioning gas gauge, you won’t know how much fuel is left in your tank, increasing your risk of getting stranded. Unless you want this to happen to you, you should fix your faulty fuel gauge as soon as possible.

Why Is Your Fuel Gauge Stuck on Full?

There are several different answers to this question. A stuck fuel gauge can be caused by a faulty fuel sending unit, a blown fuse, or damaged wiring. Sometimes, the fuel gauge itself might be the problem.

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How To Fix a Faulty Fuel Gauge

Fixing a faulty fuel gauge can be hard, mostly because it might take some time before you figure out the culprit. However, just because diagnosing the issue is time-consuming doesn’t mean fixing it has to be complicated too. Here are a few tips on how to fix a gas gauge that isn’t working: 

Prepare the Necessary Tools

Time is money, and you really don’t want to waste your time going back and forth into your storage closet just to look for your tools. For a much more efficient DIY session, have all of your tools within reach. Prepare your multimeter, owner’s manual, and your toolbox. You’ll likely need an electrical cleaner and fuel system treatment too.

Perform an Instrument Cluster Self-test

Go through your owner’s manual and look for instructions on how to perform the instrument cluster self-test procedure. The process differs for every vehicle, but for modern cars, you usually have to press the odometer button and turn the headlights on and off a few times.

If the fuel gauge needle doesn’t do a full sweep during the self-test procedure, then you’re likely dealing with fuel gauge issues. If the needle moves as expected, then you’ll have to move on and perform other diagnostic tests.

Check the Fuse

Have you noticed issues with any of your other gauges recently? If you have, then there’s a big chance you’re dealing with a blown fuse. Locate your vehicle’s fuse box, and check the condition of your fuel gauge fuse. One look should be enough to tell you if it’s blown and needs replacing.

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Test the Fuel Sending Unit

You’ll need a multimeter for this. Locate your vehicle’s fuel sending unit, and then use your multimeter to test its resistance. In some cases, you might have to remove it first before you can test it with your multimeter.

For older sending units, a functioning sending unit should read “0-30” or “0-60,” where an empty tank will read 0 ohms and a full tank will read 30 or 60 ohms. If the resistance is off by a lot, then you’re likely dealing with a faulty fuel sending unit.

You can try fixing this with a fuel system cleaner, which can help clear any dirt clogging the unit. In some cases, however, you’ll have to replace the entire fuel pump assembly to fix your stuck gas gauge.

Check the Fuel Gauge’s Voltage

Sometimes, the reason why your fuel gauge is stuck on full is because of the gas gauge itself. You can check the voltage of the gauge with your multimeter to see whether or not this is the case for you.

After consulting your owner’s manual, pull your instrument cluster out of your dashboard carefully. Then, set your multimeter to 20V DC and test the wiring connected to the gauge. If the reading doesn’t match the voltage listed in your owner’s manual, then you likely have a faulty gas gauge that needs replacing.

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Inspect the Wiring

Have you tried inspecting the wires of your gas gauge? Corroded or loose wiring can result in inaccurate gas gauge readings. It might be time-consuming, but visually inspecting your wires is relatively easy. You should replace any damaged wiring and tighten any loose wires. Cleaning dirty wiring is also a good idea, as long as you use an electronic cleaner.

What Is a Fuel Gauge?

Located on your dashboard, a fuel gauge is a digital or analog gauge that lets you how much fuel is left in your tank. A sending unit connected to the fuel tank sends information to the gas gauge, which moves the analog needle to point to “E” when it’s empty or “F” when it’s full.

About The Author
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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