The manifold absolute pressure sensor, or MAP sensor, measures the pressure (vacuum) in the intake manifold. It then sends this information as voltage signal that varies to the ECM. Determining the pressure of the air helps specify and control the amount of fuel the vehicle needs to run properly in various conditions.
When a MAP sensor fails, then it could cause an increase in fuel consumption. The most common correction of the problem is to have the sensor replaced.
A manifold absolute pressure sensor is covered under the federal emissions warranty. It is also covered under the manufacturer's factory warranty if the time and mileage limits are longer than those of the emission warranty. Also, there are extended car warranties available that will the MAP sensor under the more comprehensive plans.