Throttle Position Sensor: Description and Operation

Throttle Position Sensor:

This sensor is used to send input signals to the engine controller to indicate the current angle of the throttle blade. This sensor is a variable resistor that has a 5 volt reference signal applied to it by the engine controller. The Throttle Position Sensor (TPS) sends signals back to the engine controller in the range of approximately 1 to 4 volts, depending upon the throttle shaft angle. The engine controller uses these input voltages to determine the current position of the throttle.

An input voltage of approximately 1 volt indicates a minimum throttle opening or idle condition. An input voltage of approximately 3.5 volts would indicate a maximum throttle opening or wide open throttle condition.

The Throttle Position Sensor's (TPS) input is used to determine when the 3-4 upshift or the 4-3 downshift (automatic transmission with overdrive) should occur. The Throttle Position Sensor (TPS) is located on the top of the fuel injection pump, and is only used on vehicles with automatic transmissions.