2002 Buick Century fuel gauge problems are most commonly caused by a blown fuse, wiring issues, bad fuel sending unit, malfunctioning fuel gauge, and damaged instrument cluster.
Keep reading this article to find out more about these issues that cause the Buick fuel gauge problem and learn how you can fix them. We’ll also discuss how fuel gauge actually works and when their reading is accurate. Let’s begin!
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How Does A Fuel Gauge Work
Before we get into the common fuel gauge problems you’re facing with your 2002 Buick century, it’s important that you have a clear understanding of how fuel gauges work. That’ll make it easier for you to diagnose the problem.
When you start the car, the fuel gauge goes to full at first, then comes to empty, and then shows you the current amount of fuel in your car.
Though modern cars have a digital gauge instead of an analog one, both of them operate in the same manner.
The process of your fuel gauge showing the correct fuel level starts at the fuel tank. A small float sits in the car’s fuel tank that’s called the fuel-sending unit. It sits on top of the fuel.
The higher the fuel level, the higher it floats. It changes its position depending on the amount of fuel in the vehicle.
This fuel-sending unit is connected to a thin metal rod that scrapes up against the resistor. This resistor sends an electronic signal to the fuel display. This signal is powered by the battery in your car via a small coil.
The lower the level of fuel, the more current the resistor sends to the fuel display and it gets closer to the empty mark in your fuel tank.
If the fuel level is high, the resistor sends a small current and the needle stays closer to the full mark in your fuel gauge.
Note: You can also read how to clean the Fuel Pressure Regulator.
2002 Buick Century Fuel Gauge Problems [5 Easy Fixes]
How to tell if the fuel gauge is bad isn’t exactly rocket science. The symptoms are obvious and even someone who has never worked on car parts before can tell when the fuel gauge isn’t functioning properly.
The main problems that happen when the fuel gauge isn’t working properly are the 2002 or 2000 Buick century fuel gauge fluctuates, reads high when the fuel level is low and reads low when the fuel level is full.
It can also trigger the low fuel light even when there is sufficient fuel in your car. So, now you may be wondering how to diagnose a bad fuel gauge. Here are the most common reasons that cause issues with the fuel gauge and how you can fix each of them:
1. Blown Fuel Gauge Fuse
The first thing you should always check when you find your 2002 or 2001 Buick century fuel gauge not working properly is the fuel gauge fuse. The fuel gauge fuse is commonly located in the fuse box on the driver’s side.
But you may also find it under the hood. Refer to your owner’s manual if you’re having trouble finding the location of the fuse. Once you have located the fuel gauge fuse, see if it’s broken.
If the fuse is broken, replace it with a new fuse. If there are no other issues that are causing any electrical problems, replacing the fuse will fix the problem for good. But you’ll have to keep troubleshooting if the fuse keeps blowing.
2. Wiring Issues
Your fuel gauge is an electrical component and it’s powered by the battery. Any issues in the wiring system can cause it to malfunction. If any of the wires leading up to the fuel gauge is disconnected or has a loose connection, the fuel gauge won’t work properly.
Diagnosing wiring issues is easy but it can take a lot of time. Start at the gas tank and inspect the wiring harness that powers the fuel pump and the fuel-sending unit. Make sure you check the ground connection to the sending unit.
Exposure to certain elements like salt, sand, snow, or water being splashed on your car can cause your wires to get corroded. Corrosion can also keep the fuel gauge from functioning properly.
Once you’ve done a thorough visual inspection of your car, you’ll find the damaged and corroded wires. Clean the corroded wires and replace the wire if it’s damaged. Make sure all the connections are good and that should fix the fuel gauge issue.
3. Bad Fuel Sending Unit
The fuel-sending unit is a vital component that makes the fuel gauge function. This sending unit is in constant motion when the vehicle is moving and it scrapes up against the resistance.
It can get worn out with time and lead to an open circuit that causes inaccurate readings. If you’re wondering what causes the fuel gauge to fluctuate, a faulty fuel-sending unit is the most common reason behind it.
To inspect the fuel-sending unit in your car, you’ll need a multimeter. You’ll need to access the sending unit and inspect it with a multimer.
It’s also a good idea to fill up your fuel tank as you’ll know what reading to expect. Refer to your owner’s manual to find out the Ohm rating of the sending unit.
Suppose, your fuel gauge works on a 0-60 ohm rating. If your tank is empty, you should be getting no resistance and the multimeter should read 0. On a full tank, you would get full resistance and the fuel gauge should read 60.
But if you have a reading that is not close to 60 on a full tank, that means your sending unit has gone bad. The float or the arm of the sending unit can also be broken which can also cause a wrong fuel gauge reading.
When the reading is off only by a few ohms, you might get away by cleaning it with a bottle of fuel system cleaner. But in most cases, you’re gonna have to replace the sending unit so that the fuel gauge can work normally again.
4. Malfunctioning Fuel Gauge
It’s possible for the fuel gauge itself to go bad and give a faulty reading. There are two terminals in the fuel gauge. One wire is connected to the ignition to receive power when you turn the car on and the other comes from the fuel-sending unit.
Check the fuel gauge for continuity with a multimeter and you should get 12V reading. If you don’t, then there are power issues in your car. Then, keep on checking for continuity between the dashboard and the gauge.
If there is no continuity, it means that there’s a break in the wire. You can check the gauge by removing it from the information cluster and checking for resistance just like you did with the sending unit.
How to fix the fuel gauge in my car? You have to replace the fuel gauge when it’s malfunctioning. Many people mistakenly diagnose a faulty fuel gauge when the sending unit has gone bad. So, make sure that the sending unit is okay before you diagnose and replace the fuel gauge.
5. Damaged Instrument Cluster
It doesn’t happen often but the fuel gauge can also show the wrong reading if the instrument cluster is damaged. You can easily diagnose the instrument cluster by a self-test in your 2002 Buick century.
Here’s how you can test the instrument cluster on your Buick century:
- Put the key in the ignition and keep it at the 0 or 1 position.
- Press and hold the Sel/Reset knob or button.
- Turn on the headlights.
- Turn on the ignition switch.
- Turn the headlights off while still pressing the Sel/Reset button within five seconds.
- Release the button.
- Press and release the button three times repeatedly.
That should begin the instrument cluster test and you’ll know the results. If you want to protect the longevity of your headlights, you can take off the fuses before you start this test.
You’ll have to replace the instrument cluster if you find that it’s damaged after performing the self-test. You can find an instrument cluster for your 2002 Buick century and replace it yourself.
Are Fuel Gauges Accurate
Fuel gauges are accurate oftentimes if they’re working properly. But there are a few scenarios when you shouldn’t expect your fuel gauge to function properly:
Immediately After Filling Up the Fuel
When you fill-up the tank in your car, you may have noticed that it takes a while for the fuel gauge to start going down. The main reason behind this is the placement of the float in the fuel tank.
The fuel-sending unit or float is generally placed near the top of the tank instead of directly at the top of the tank. Because of this gap, the level of fuel dropping doesn’t appear in the fuel gauge.
But once that gap is fulfilled and the fuel level comes down, it functions normally once again and gives an accurate reading from there on.
An Empty Fuel Tank
The fuel-sending unit will never go to the absolute bottom of the fuel tank. So, you may get a reading that the fuel level is empty before it’s actually empty. But when that happens, you should realize that you’re very close to running out of fuel as the float has reached the lowest it can go.
Driving Up Steep Surfaces
You cannot trust the reading of the fuel gauge on steep surfaces. When you’re driving on an incline, the fuel will reach the lower part of your vehicle but the fuel gauge will stay in its original position.
The fuel gauge will show you more fuel than your current level if it settles at the lower part. It’ll show you less fuel than what you have it settles at the higher part. But once you get back to a level surface, it’ll automatically be fixed and start to give you an accurate reading.
Is it safe to drive with a bad fuel gauge?
Whether it’s safe to drive with a bad fuel gauge depends on the person. If you’re diligent at refilling your fuel from time to time, you’ll most likely not have any problem with a bad fuel gauge.
Why does my fuel gauge stay empty?
The gauge that always shows empty doesn’t have any resistance to the ground. The sending unit wire is probably touching the ground and causing this issue.
Why does my fuel gauge stay on full?
The gauge stays on full when it’s receiving an infinite resistance signal. It could be due to a break in the wire, a faulty sending unit or the fuel gauge itself has gone bad.
How much does a fuel gauge cost to fix?
The cost of a fuel gauge is anywhere from $50 to $250 for most vehicles. That’s all you’d need to spend if you can replace it yourself. Otherwise, you’ll have to spend an additional $100 or $200 for a mechanic.
It can be fearful to not know the right amount of fuel in your car with certainty because of a bad fuel gauge and keep on driving. But now you the main reasons that cause 2002 Buick Century fuel gauge problems and how you can diagnose and fix each of these issues.
Hopefully, you won’t have to worry about troubleshooting a bad fuel gauge after completing this article. Drop a comment below if you have any more questions about fuel gauges.