The check engine light often referred to as the money light is probably the most common fault light to come on. This light refers to all the components relating to the smooth running of the engine. Components would include MAF sensor, temperature sensors, fuel system, ignition system, gas metering system and many more sensors, valves and solenoids. This light could also point to a mechanical fault like vacuum leak, leaking exhaust and any number of the mechanical components making the engine run.
In this case it is imperative to properly diagnose the problem and not simply start changing components. It is also important to be able to read live streaming data to clearly identify the fault. This can save you time and money