Neutral Safety Switch: Description and Operation

PURPOSE
Prevents starting the vehicle except when gear selector is in "P" or "N" positions. Signals the transmission control module and the ECM of gear shift position.

OPERATION
The transmission control module monitors the switch and relays gear select information to the ECM. The ECM uses gear position input from the switch in its calculations for these outputs: fuel injection quantity, idle air control, purge control, ignition timing control, A/C cut-off control, EGR system control, and variable inertia charging system control.