The easiest way to look up engine service light codes is to search for the code online and find a free listing of codes. You can also look them up in a shop manual for that model of car.
You can access the specific engine service light code by using a vehicle diagnostic scanner. To use one, access the diagnostic link connector. This is usually located under the dashboard beneath the steering wheel. Plug the scanner into it, and read the code. Some scanners tell you what the code means, which prevents the need for looking up that specific code. However, more research may still be needed as sometimes codes can signal several potential problems.
If you are using a less expensive scanner that does not tell you the code, there are many free listings available. Shop manuals may be more reliable and provide additional information that can help you diagnose the problem. There are hard-copy shop manuals available for sale, and most cars also have an online version to which you can pay to subscribe. Some older manuals may be online for free, but this is unusual.
Some automotive parts stores and mechanic shops also offer free engine code look-ups. You can also check your owner's manual as some engine lights have specific meanings in some models of cars.