Circuit/System Description
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The park/neutral position (PNP) switch is externally mounted on the transmission manual shaft. The switch consists of five separate circuits, four of which indicate gear selector position to the transmission control module (TCM), and one that indicates park/neutral position to the ECM. As the gear range selector lever is moved, the state of the P/N switch may change, causing the park/neutral signal circuit to open or close. An open circuit or switch indicates a drive range and a low voltage, 0 volts, signal at the engine control module (ECM). A closed circuit or switch indicates PARK or NEUTRAL and a high voltage, 12 volts, signal at the ECM. The ECM uses the PNP Switch status in order to enable starter operation.