When a person buys a car, he usually expects it to run well for a long time. To this end, car manufacturers have developed sophisticated computer systems that keep the car in check and help to keep it running smoothly. Those systems will also light up the check engine light when there is something wrong with the car. A car diagnostic is a test that tells a person what is causing the check engine light to turn on. Once the problem is identified using this system, the mechanic can go forward in fixing it.
Many cars like Porsche now have a computer system that keeps it in check. This computer system is constantly receiving information from the different sensors in the engine and adjusting those systems so the car can run smoothly. It is this computer system that also controls the check engine light. When there is a problem the computer cannot fix itself, it triggers the light so a mechanic can identify and solve the problem. The system also produces a code that can be used to help identify the area and nature of the problem.