So you are driving down the road, and your check engine light comes on.
There are basically 3 modes for the Check engine light. Off, On, and Flashing.
All Systems Checking out good!
Check Engine Light on Solid
If the light came on solid, but car feels like it is running fine, nothing seems unusual, if you recently fueled up the car, first thing to do is check to make sure you tightened the gas cap nice and tight. No need to panic, the light can come on for lots of reasons, drive like normal, and try to bring it by soon to have us scan the computer and see why the light came on. The computer stores this information and they are basically clues as to what may be going on. If not a serious issue, we may just clear the code, log what it was, and if the light comes on again, bring it by to have it diagnosed. Now if you keep driving with the light on, and other issues more serious come up, the computer will store them, but since the light is already on, you have no warning.
Check Engine Light Flashing
This is really bad, you probably are already thinking the same. The car is misfiring and running terrible. Rough, lack of power, etc. You should drive the least you can. Like find a safe place to pull over soon! If you are close to home or our shop, you could probably make it, but if you drive too long, you will cause other damage. Misfiring can be sending raw fuel mixed with air that did not ignite in the engine down past your Oxygen Sensors and into extremely hot Catalytic Converters. You can melt down the converters fast! They may be Cherry Red and Smoking! Now you have a misfire problem to have fixed, which isn’t usually too big of a deal, and now you need new Catalytic converters and possibly OXS sensors. What you ruined can cost way more to fix than what caused it! So do not drive long with a flashing check engine light!