Is your "Check Engine" or "Service Engine Soon" light on? If so, you may need to "service your engine soon," but how can you know for sure what is wrong without taking it to a dealership and getting charged for a diagnostic test. The car still runs fine, so what's the big deal.
There are a wide range of things that can trigger the unwanted light. It can be anything from a misfiring cylinder due to a bad spark plug, to a bad O2 sensor, to an air fuel ratio outside the optimum parameters. There is an easy and cheap way to check. In our area of georgia, I have found that most of the Autozones carry the OBD1 and OBD2 diagnostic computers which can scan for trouble codes. They offer this as a free service to their customers, which can save the $ 35 to $ 80 I have seen charged for the same thing.
Once these error codes are received from your computer, you have a clue as to what the problem is. You can now do a simple Google search to see what the codes mean specifically for your vehicle. In a lot of cases, it will tell you exactly the faulty component, such as which O2 sensor or cylinder is failing. You can now purchase the parts you need and save time and money on the repairs and service.
Beginning in the 1990's most cars began coming equipped with on board diagnostics, or OBD codes. Also called trouble codes, these codes help diagnosis problems your vehicle is having, sometimes before they are bad enough for you to be stuck on the side of the road. If the warnings are acted upon, you can save yourself in the long run. There are two different types of on board diagnostics depending on the make and year of your vehicle. OBD 1 cars were produced up to '95 and OBD2 runs from '95 / '96 and up. Check your vehicle owners manual to know for sure.
When your check engine or service engine soon light come on, be sure to go and have the codes read. Do not wait for your car to stop running before you take it in for repairs, because the cost of waiting is usually higher.
To check your trouble codes, you can visit one of my favorite sites for trouble code information located at the code database. Here you can find all the codes for all makes and models sorted by year and code. Armed with the right info, maintenance and service are a breeze for any vehicle.
Hopefully you have some useful information to use when you encounter the dreaded check engine light. Stay up to date on the maintenance and service and your car should return the favor by being reliable.