BMW X5 Fuel Tank Cap
Troubleshooting your BMW X5 Fuel Tank Cap Problems
Often made from plastic or metal, your BMW X5's fuel tank cap is one of the auto parts that you least expect to wear out. Its primary function is to keep the fuel from spilling from the tank to other nearby components. You may not be aware, but it is in great risk of wear and tear due to the nature of its function. You might be surprise when it suddenly gets stuck just when you are about to have your tank filled. Before that happens, here's how you can troubleshoot some fuel tank cap problems on your own:
Fuel tank cap is stuck.
You are rushing to the airport for your flight and you noticed that you're running out of gas. You pulled over to the nearest gas station to have your gas tank refilled. However, the gasoline boy tells you that the fuel tank won't budge. You even tried to do it, but it still won't. Well, this is a not-so-common situation for BMW X5 owners. This could be due to an excess vacuum in the tank that is pulling the cap or the tank may have become over-pressurized. Try using a rubber wrench the size of the cap and turn it carefully. If it won't give in on your first try, let your car sit for some hours to let the pressure decrease. The cap might also be wearing out from the inside, which makes it harder to turn.
The engine light is on.
When there is a gas leakage on your vehicle, the "check engine" light usually turns on. You can use your car's computer to determine the error code that is possibly causing the problem. Error code "P0440" means your gas cap is loose, while "P0400" indicates that a broken seal is causing the tank to leak and it needs a more urgent fix. You need to check your fuel tank assembly for any crack that could be the source for leaks. Usually, it is due to a loose cap that only needs to be tightened. But if you've already checked the tank for damage and the light keeps blinking, chances are, the cap is already worn-out and it cannot properly seal the tank.