The theory and operation of any mass airflow sensor is pretty basic. What you have is a wire in the Airstream entering the engine. It has current running through it. This current heats up the wire. As the air flows over this wire, it changes the resistance in the wire. The change in resistance shows the ECM, how much air is entering into the engine. But by heating up a wire that is in the Airstream entering the engine, even after the filter, it can have contaminants that can stick to that hot wire and cause faulty readings about the air entering into the engine. This can cause numerous codes because either it’s under or over reporting the air entering the engine, and it’s not very accurate. And using the oxygen sensor, the ECM can see issues with the mass airflow sensor. So what can you do both for maintenance and for service and diagnostics to confirm a mass airflow sensors functioning properly?
Well, there are cleaners. Some of these cleaners can remove that junk that gets stuck to the wire, but it has to be specifically formulated for mass airflow sensor cleaning. Do not use carburetor cleaner and do not use brake cleaner. These can leave a residue on the wire. That can change the resistance as the air flows over and cause issues with the sensor. Also, some of the chemicals in a non-approved cleaner for a mass airflow sensor while they can degrade the housing and the plastics inside. So there are two cases where you use a cleaner one for maintenance in case you know the vehicle’s not running properly or it’s reached that interval, and maybe cleaning that mass airflow sensor will help to improve performance. The other one, you could also use it for diagnostics to make sure that that sensor is functioning properly. But the critical thing here is to use the appropriate cleaner for the mass airflow sensor. I’m Andrew Markel. Thank you very much.