Jim Grant's Tech Tips
MAF Sensors and Aftermarket (K&N) Air filters
What are the potential downfalls utilizing an aftermarket style (K&N) air filter in a 2002 and newer computer controlled automobile? Can it damage the MAF sensor or gum it up enough to cause problematic fault codes and transmission shifting anomalies?
- Anthony Decarlo
High flow air filters as the type you describe can create problems, but the majority of those problems are the fault of the driver of the vehicle. High flow filters have to be maintained with regular cleanings and treatment of the filtering element. Failing to do so allows fine debris to pass by the air filter. Most of today’s vehicles are equipped with a Mass Air Flow (MAF) meter that measures the amount of air entering the engine. The MAF meter has a heated wire that is cooled by the passing air. The processor in the MAF meter calculates the air flow into the engine by how much electricity it takes to keep the heated wire hot. When the engine is turned off the processor performs a burn off function of the wire. This burn off function is to burn any debris that may have collected on the heated wire. The problem with high flow air filter is that they have to receive very regular maintenance If they do not, too much fine debris gets by the filter and collects on the heated wire of the MAF sensor. So much so, that the burn off function doesn’t clean it off. As debris builds-up, the heated wire becomes less sensitive to the cooling affect of the air passing by. This results in miscalculation of the air entering the engine. Over time, the problem can get so bad that the check engine light will turn on and there will be driveability problems. The el-cheap-o air filters can cause the same problem. Not to worry, all you need to do is service the air filter and replace the very pricey MAF sensor.