Very happy to finally hear from someone who is smart enough to be concerned, but in this case most likely you have a minor problem. The Engine Computer detected a problem, set a diagnostic fault code, and turned the light to tell you. There are some generalizations you can make related to how that light acts. There are well over a thousand potential fault codes. Only about half of them relate to something that could adversely affect emissions, and those are the ones that must turn the light on. If the problem is really serious, too much raw fuel is going into the exhaust and is going to overheat the catalytic converters. That's a real expensive repair in addition to what caused it, and you're supposed to stop the engine as quickly as possible. The Check Engine light will be flashing.
With the least severe problems that still affect emissions, the light will turn on, and if the problem is intermittent and stops acting up, the light will turn off while you're driving. It's pretty safe to keep driving. If the problem is more severe, the light will turn on, and it will "latch" on, or stay on, even if the problem stops occurring, and it will not turn off until you turn the ignition switch off and restart the engine. That's what happened to you. It's still probably okay to drive it like that, but don't ignore it completely. The light will stay off until the problem occurs again.
If it's still more serious, the light will turn on, and even if the problem goes away, the light will still be on even after restarting the engine.
There's a couple of important things to know about those fault codes. First of all, especially with intermittent problems, do not disconnect the battery or let it run dead. Doing so almost always erases codes stored in Engine Computers, then that valuable information will be lost. Second, be aware that fault codes never say to replace parts or that they're defective. They only indicate the circuit or system that needs further diagnosis, or they indicate an unacceptable operating condition that needs to be diagnosed. Many auto parts stores will read the codes for you for free, then try to sell you parts because parts is what they understand. In fact, if a sensor is referenced in the code, that sensor is actually defective only about half of the time. A wiring problem associated with that sensor can set the same codes.
Friday, January 3rd, 2014 AT 1:03 AM