Transmission Position Sensor/Switch: Description and Operation

PURPOSE
The Park/Neutral Position (PNP) switch gives an indication of transmission load to the Powertrain Control Module (PCM). This information is required for adjusting fuel/air ratio and idle speed.

OPERATION
When the transmission is in gear the PNP switch is normally open. This results in a high voltage on the PNP output pin 30. When the transmission is shifted into neutral or park the PNP switch is closed and ground is applied to PNP output pin 30.