Throttle Position Sensor: Description and Operation

Throttle Position Sensor:

This sensor found on automatic transmission applications only, is used to send input signals to the PCM 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 PCM. The Throttle Position Sensor (TPS) sends signals back to the PCM in the range of approximately 1 to 4 volts, depending upon the throttle shaft angle. The PCM 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.