If your check engine light comes it is not the end of the world or at least it may not be as expensive as you may think. The first item to check is your gas cap is it tight or have you filled recently while the engine was running, if so wait about 6 key cycles, engine from cold to hot and a several RPM changes enough to cause a vacuum change, this should turn it off. If not then visit one of your local parts stores most will check for codes at no cost. Beware however it is there job to sell parts so if the code indicates a bad EGR valve they will try to sell you one. However check for other problems first, are all the hoses and electrical connectors secure. It is a good idea to unplug all electrical connectors to the effected sensor, this will sometimes help, rarely but it doesn’t hurt. Check to see if the item needs cleaning mainly in the case of an EGR or IAC also some vehicles have a filter, Honda does on many of their IAC and Ford on the Fuel EVAP system. Still a problem then it is time to check the manual, some you can find online or visit your local library, these can also be checked online in some cases. There is usually a tree to troubleshoot the affected item. Still at a loss replace the sensor they are usually cheaper than having a shop check it out. The only exception to this is the O2 sensor if you have no exhaust leaks if it throws a code they are usually defective. They also require special equipment to diagnosis.Do not put a match book cover or a piece of tape over the light as this will lead to more expensive repairs down the road. I have seen the light bulb removed in several cases. Just remember don’t panic your engine is not going to explode although I have heard of parts stores hinting that this may happen.