It’s what almost every motorist has to go through once in a while: the Check Engine or Service Engine Soon light. If this warning light stays on, it means that your vehicle’s computer has detected a problem that can affect your vehicle’s fuel economy and emissions.
Let’s explore your options on how to deal with it. First, shortly how it works. Your car has a computer (in the photo) that controls the powertrain (engine and transmission). This computer is called Powertrain Control Module (PCM). It works by monitoring signals from various sensors and adjusting the engine and transmission performance for better fuel economy and lower emissions.