When your check engine light comes on, it does not necessarily mean that you should automatically shift into panic mode. Instead, stay calm. Sometimes, the check engine light comes on for really benign things, like a gas cap that is not tightened enough. Other times, the check engine light could be alerting you to something that is more serious.
As a general rule, though, if the check engine light is just on, it is less ominous of a sign than if the check engine light is blinking. A blinking check engine light means that something pretty serious is wrong with your car, and you should pull over as soon as it is safe to have the vehicle checked out by a professional.
The customer is really, in a long run, potentially hurting their pocket book by leaving that light and ignoring it, said Jim Collins, one of the national training team leaders for the Ford Motor Company. This is because when the car is having some sort of problems and has alerted you by turning on the check engine light, but you pretend you do not see it and continue to drive the car, the problems often get worse and require more time and money to fix.
One of the reasons that your check engine light may be on, besides the best case scenario of a loose gas cap, is that you are pushing your car too hard for the engine to keep up. If you are towing something, for example, and your car is struggling to get enough power to the engine, often times the check engine light will come on. In this instance, you could stop towing the load or try going slower.
There are a slew of other reasons why a check engine light may come on, too. Because it does not make sense for car manufacturers to have a dozen or so different warning lights, many times problems that do not have their own warning light get lumped under the check engine light category.
The only way to really determine what is wrong with your car is to take it to a mechanic, who will hook it up to a special computer that will read the problem code your car is giving off. It may cost $50 to have this test run, but the peace of mind that it can give you to know that the warning is not serious may well be worth the cash.