Circuit Description
WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The manifold absolute pressure (MAP) sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The engine control module (ECM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit, and provides a ground for the low reference circuit. The MAP sensor provides a voltage signal to the ECM on the signal circuit relative to the intake manifold pressure changes.