The check engine light is one of the mysteries of car ownership. When illuminated, it could indicate any number of problems, or it could mean nothing at all. However, that doesn't mean you should ignore the light when it comes on, which is what many drivers choose to do.
Covering up the warning light or simply assuming that the only problem is the light itself can result in worse, more expensive issues down the line. It is best to investigate the probable causes of a check engine light as soon as possible to avoid incurring further damage to your vehicle.
Something as simple as a change in the weather, or a loose gas cap can trigger the light. In the case of weather changes, such as a dramatic increase or decrease in humidity, the light should shut off on its own after a little while. While you are waiting, with fingers crossed, to see if the light will go out on its own, you can check a few other things that may be the root of the check engine light problem.
Last year, CarMD.com released its Vehicle Health Index, which included the top five most common problems that were tied to that pesky dashboard light for cars built in and after 1996. Until 2010, loose gas caps were found to be the most common issue, and they accounted for 10 percent of all fixes.
Pop the door covering the gas cap and wiggle it gently. If it's loose, tighten it and check to see if the light has gone out, which could take some time as the car adjusts. A loose cap will indicate to the vehicle's computer that there is a leak in the vapor recovery system, and it will take a bit of driving for the light to turn off if this is the issue, so don't panic if it doesn't shut off right away.
You can also take this opportunity to check for any cracks or damages in the rubber ring that ensure the seal between the cap and the gas tank is airtight. If it is visibly in poor condition, you should consider replacing it, as a bad seal can have a negative effect on the vehicle's fuel efficiency, and it might be the reason the light is on.
In 2010, loose gas caps took second place to faulty O2 sensors in CarMD.com's assessment of common problems. The sensor is a an integral part of the emission control system. It controls the amount of air and fuel that enter the combustion chamber to ensure that the mixture is neither too rich nor too lean so the engine delivers an optimal performance and produces the least amount of emissions possible.
The oxygen sensor adjusts the air flow in the engine depending on the environment, and it can adapt to different altitudes and temperatures in the air and engine. If there is a problem with the O2 sensor, your vehicle will not be able to regulate the fuel-to-air ratio properly. This can result in poor performance and a decline in fuel economy.
If the check engine light starts to blink, this typically indicates a more serious problem, such as a misfire that could damage the catalytic converter. Since the converter operates at high temperatures, any issues can drastically increase the risk of a fire or other major problems.