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Gas Cap

All modern cars are equipped with an Evaporative Emission Control (EVAP) system. The EVAP system prevents fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system collects and temporarily stores the fuel vapors in the charcoal...

Hi there You should have the computer Check Engine Light scanned by a mechanic. Once the codes are received and the pinpoint test is completed, you should have a diagnosis of the failed component. A lot of times a code...

You will need to have the computer checked for codes since a leaking in the fuel vapor system can cause the vehicle to think the cap is leaking. You may have a bad or leaking vapor vent or purge valve....

The “check fuel fill inlet” warning light means that there is a problem with the fuel tank fill seal. The seal could be missing, loose, damaged, distorted, or there is debris in the fuel fill inlet, and/or there is a...

If you need a gas cap, especially if you are trying to resolve what you believe might be a cap related fault, use an OEM (dealer supplied) cap. Using a genuine OEM cap of the design supplied when the car...

Hi there. The message is on for the fuel system is not able to build up pressure. Check the fuel cap seal and see if the seal is cracked or broken. A broken seal on the fuel cap will cause...

There can be other issues causing the gas cap fault. It may be best to have a certified technician look into the gas cap fault (https://www.yourmechanic.com/services/gas-cap-replacement). Rare but one possibility can be damage to the fuel filler neck itself. If...

Your fuel tank is going into a vacuum when the engine is running. The vacuum condition is causing the fuel tank to collapse and the gas cap is supposed to let in fresh air from the outside to keep the...

Hi there. If water is getting into the fuel door and flooding the gas cap area, first check the gas cap for a good seal. The cap should seal the fuel and vapors in and not leak out. If the...

Hi there. When the fuel cap (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-gas-cap) is not securely fastened to the tank, it can create vacuum issues inside the tank; which triggers the error code to be stored in the ECU. The error will then trigger the check...

The first to do is to look at the gas refueling location to see if you have the no cap design or the cap is just missing. If you have the no cap design then you do not have to...

This is true, but there are countless other reasons for an illuminated Check Engine Light (https://www.yourmechanic.com/article/what-does-the-check-engine-warning-light-mean) as well. A loose gas cap will typically set an evaporative emissions (EVAP) system code, such as P0440 (https://www.yourmechanic.com/article/p0440-obd-ii-trouble-code-evaporative-emission-control-system-malfunction-by-jay-safford_2) or P0455 (https://www.yourmechanic.com/article/p0455-obd-ii-trouble-code-system-gross-leak-evaporative-emission-by-john-nelson). The EVAP...

For the case of the gas cap leak you will need to have a smoke test and cap test done to see where the evaporative system is leaking. In order to do this will require the system put in test...

First, remove and reinstall the gas cap, clear the code P0455 (https://www.yourmechanic.com/article/p0455-obd-ii-trouble-code-system-gross-leak-evaporative-emission-by-john-nelson), and drive the vehicle for a few days and see if the code comes back. If the code comes back on, then either the gas cap (https://www.yourmechanic.com/services/gas-cap-replacement) needs...

Try removing the gas cap and putting it back on. While the gas cap is off, check the seal on the cap and see if there is any cracks or damage to the seal. If the seal is good and...

Hi there. Check the gas cap seal and see if there is a crack on it or if there is a distortion on the seal. If there is, I recommend replacing the gas cap. The gas cap seal is designed...

Hello there, a few common faults will cause your 2004 Hyundai Sonata to have issues removing the gas cap. In cold weather the gas cap seal can become stuck, this will allow the gas cap to turn but not fully...

Hi there. To remove the gas cap that broke off, get a pair of needle nose pliers and use it to remove the gas cap. Try to locate a part of the gas cap that you can grab with the...

The computer will run self tests as the vehicle is turned on, and while the vehicle is driving. There are certain circumstances for each test that must be met for the computer to turn off the check engine light. The...

Diagnostic Trouble Code P0455 (https://www.yourmechanic.com/article/p0455-obd-ii-trouble-code-system-gross-leak-evaporative-emission-by-john-nelson) has causes in addition to a faulty or loose gas cap. In your circumstance, the first thing you should do is reset the Check Engine Light (https://www.yourmechanic.com/services/check-engine-light-is-on-inspection) which will erase the existing codes. Then see...