Tire pressure monitoring system or the annoying light that keeps coming on on the dashboard.  The Tread act by Congress required all passenger vehicles sold after 2007 be equipped with a tire pressure monitoring device.

The Different types of Tire Pressure Monitoring systems

Direct and Indirect TPMS

There is a sensor in each wheel that monitors the tire pressure and transmits this information to a control module in the car.  

Volkswagen, BMW and some Toyota's use indirect tire pressure method.  It uses and abs system and compares individual wheel speeds.  When one wheel deviates beyond the threshold the light will illuminate. 

Benefits of TPMS

Improves fuel economy.  Tire last longer being properly inflated.  Car handles properly

Our diagnostic procedure when the light comes on.  Our first step is to check the tire pressure, if one tire is very low we will look for a leak in the tire.  If a customer returns with a light on at this point we will scan the sensors in the tire to confirm operation and scan the module in the car for trouble codes.