Gas Cap Light On Odometer: What Does It Mean & How To Fix It

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Many drivers notice that the gas cap light comes on and goes off more often than usual. But they don’t know what that indicates. So, what does it mean when your gas cap light is on, and how can you fix it? 

A gas cap light is on mostly when the gas cap is missing or loosely screwed up. However, it could also be due to a clogged gas cap or computer and sensor issues. To fix it, you can replace the cap, clean it, or update the system software to fix software problems. 

Let’s discuss if it’s safe to ride when your gas cap light is on, why this light appears and how to fix the odometer gas cap light issue. 

Why Does Your Odometer Say Gas Cap?

Odometer Speed gauge in car

The gas you use to run your vehicle evaporates when exposed to open air, which may affect your engine’s performance. To avoid this, most vehicles have a gas cap that prevents gas vapors from escaping the fuel tank. 

When your odometer says “gas cap,” it often means the sensors have detected a fuel leak in the gas tank. This usually happens when you forget to put on the gas cap after filling it or if you’ve put it on loosely. 

Other reasons include an old cap, a clogged gas cap, or faulty computers and sensors. Let’s discuss these reasons in more detail: 

Missing Gas Cap

A gas tank is connected to the vehicle sensor system that sends risk indicators when it faces any problem with the gas cap. For example, when the gas cap light is on in your odometer, it typically indicates that your gas cap is missing. 

Perhaps you’ve forgotten to put it on after fueling up, or it was loosely put on or blown down by the heavy air pressure while driving. If you see it, you should immediately stop your vehicle to confirm. 

Old Gas Cap

As a gas cap ages, it’s likely to get scratches and cracks in its rubber or body. These cracks may result in fuel escaping, sending indicators to the odometer, which immediately switches the gas cap light. 

Clogged Gas Cap

If your gas cap is new and tightly screwed up, but you still see the gas light on, this probably indicates that the dust particles are sitting in its tiny rubber pores. A clogged gas cap can also make it difficult for you to get it to sit correctly on its holder, letting air or fuel pass through.   

Computer/Sensor Issues

Your odometer is connected to a computer system powered by several sensors. These sensors send risk indicators to the system, showing that the part is not working well. 

Sometimes, a faulty computer system may misinterpret the information and indicate problems in the gas cap, while the real problem lies elsewhere. 

Is it Okay to Drive with Gas Cap Light On?

You can continue driving your vehicle if you’ve ensured the real problem doesn’t lie in the gas cap. If your gas cap is missing or loosely screwed up, a flapper valve inside the fuel tank can prevent fuel vapors from escaping. 

However, pulling over as soon as possible is recommended if your gas light is on. This is because the flapper valve can withstand pressure but not for a long time, reducing engine performance. 

If the gas light is still on for no apparent reason, driving can be risky because there could be a problem with other parts, which can cause a serious accident.

The other danger is you may probably get the open fuel tank ignited by an external ignition source, causing your vehicle to blow up.  

What Should You Do to Fix the Gas Cap Problem?

Woman hand opening car gas tank cap at petrol station

Here’s what you should do when your odometer repeatedly says “gas cap”: 

  • Replace the Cap: The simplest way is to replace the old cap with a new one with unscratched rubber to prevent the fuel vapors from escaping. 
  • Clean the Cap: Before spending money to replace the gas cap, you should carefully clean it to remove dust and dirt particles from its rubber. You can use a compressed air can or other tools to provide enough air pressure to penetrate through the tiny pores of the rubber. 
  • Fix the Computer/Sensor System: If nothing’s wrong with the gas cap, you should update the system software, so it may process the information well. You can also replace the sensors if it’s necessary.  
  • Visit a Professional: If you can’t find any apparent problem with your gas cap and the gas cap light is still on, you should visit a certified technician to help you.   

How Long After Fixing Gas Cap Will Light Go Off?

The gas cap light usually goes off as soon as the problem is fixed. However, don’t worry if the gas cap light doesn’t go off instantly after fixing it, as sometimes, you may have to restart your vehicle for the light to go away. 

When you’ve fixed the gas cap problem, you may probably continue riding for about a hundred miles before the gas light goes off. 

You may need to check again if the gas cap is still loose if the gas cap light comes on and goes off more often. You should visit a certified technician for a professional inspection if it still comes on.