The air mass meter is located in the engine compartment usually adjacent to the air filter assembly. If you are going to clean the engine compartment of your car , and it has a air mass meter, be sure to avoid getting water or degreaser on or around the air flow meter. The air mass meter or sometimes called the air flow meter is used to determine the airflow that is being delivered to your engine. The air mass meter does this by sending an electronic signal to the cars computer, and thus sends the correct signal to the fuel injectors that regulate the amount of fuel that is delivered to the engine. Be very careful not to touch or get any contaminates on the electrodes on the inside of the air mass meter, as this will cause the air flow meter to fail.