Is your Check Engine light on? Is your car acting different? Is it struggling? Are you aware that there are different types of sensors which cause this light to illuminate? The OBDII system (think of this as the momma of the car) tracks and inspects the following systems and components: Misfire Detection: Checks for engine misfires, often using crankshaft speed sensors. Fuel System: Monitors fuel pressure, injection timing, and feedback control. Oxygen (O2) Sensors: Ensures accurate readings for fuel mixture control. Catalytic Converter: Evaluates its efficiency in reducing emissions. EGR (Exhaust Gas Recirculation) System: Checks flow, response, and cooler operation. Evaporative Emission Control (EVAP) System: Tests for fuel vapor leaks. Boost Pressure (for turbocharged vehicles): Monitors for overboosting or underboosting. Transmission: Monitors for issues related to gear shifting and overall performance. If one of these systems fails to stay within the designated parameters assigned by the car maker then you will see the MIL or CHECK ENGINE LIGHT illuminate. It could blink or it could stay on but either way it is definitely something not to be overlooked or ignored