When your check engine lights comes on, you may be torn between utter panic and just wanting to ignore it and hope it goes away. That's perfectly understandable. That same check engine light could come on for anything from a serious engine or transmission problem all the way down to a loose gas cap.
There's a very common misconception that the trouble codes stored in your engine computer when your check engine light comes on will specifically identify a problem. It's really more like pointing to the symptoms of a problem.
Think of taking your temperature. Say it's 101. Your heat sensor – the thermometer – tells you that your temperature is out of the normal range. But it doesn't tell you why you have a fever. Is it the flu or a sinus infection? You need more information; more tests.
For any given trouble code, there could be a number of causes. So your trained technician takes the trouble code as a starting point and begins a diagnostic process to determine the cause of the problem. And some problems take longer to solve than others.
When your engine management system logs a problem and illuminates the check engine light, your service technician will plug in a scanner, download the trouble codes and go to work tracing the cause of the problem.
That's just the first step. That's when your technician's training, equipment, databases and skill get put to work diagnosing the problem and fixing it.
If your check engine light is flashing it means that the problem could lead to serious damage. You should get to the service center as soon as possible to get the problem solved. If it's on but not flashing, you have some time to get in at your convenience.