Why does the Check Engine light come on when the cap is left off?
The fuel system in your car is a sealed system that traps harmful gas fumes. If the gas cap is left off gas is able to escape from the system. When this happens, a self-test of the performance system detects this “leak” in the EVAP (Evaporative Emissions System) and the check engine light comes on, and a code is stored.
What does it mean if your gas cap is loose?
This system monitors a number of engine and emissions-related components to ensure that everything is in working order. If your gas cap is not properly attached, you may see a “Check Engine” light or a “Loose Cap” warning light on the dash.
How to reset the warning light gas cap that is loose?
Open the door. Grasp the gas cap handle and twist it counterclockwise to unscrew it. Remove it. Replace the gas cap. Removing and replacing it ensures the thread seals properly, in case it wasn’t before. Turn the gas cap clockwise to tighten it. Continue turning until you hear it click three times. This ensures it’s seating properly.
What to do if you lose your check engine light?
Assuming that the check engine light is directly due to the missing gas cap and not some other reason, simply replacing the gas cap and driving the vehicle for 100 miles or so will allow the system to reset itself.
Can a new gas cap turn off the Check Engine light?
Searching the internet will turn up tons of results saying that a new gas cap will turn your check engine light off. The reality is, it won’t do a thing if your check engine light is on because you need a new O2 sensor (or any other problem).
This system monitors a number of engine and emissions-related components to ensure that everything is in working order. If your gas cap is not properly attached, you may see a “Check Engine” light or a “Loose Cap” warning light on the dash.
Open the door. Grasp the gas cap handle and twist it counterclockwise to unscrew it. Remove it. Replace the gas cap. Removing and replacing it ensures the thread seals properly, in case it wasn’t before. Turn the gas cap clockwise to tighten it. Continue turning until you hear it click three times. This ensures it’s seating properly.
Assuming that the check engine light is directly due to the missing gas cap and not some other reason, simply replacing the gas cap and driving the vehicle for 100 miles or so will allow the system to reset itself.