Throttle Position Sensor: Description and Operation

Throttle Position (TP) Sensor:

DESCRIPTION
The non-adjustable Throttle Position (TP) sensor, is mounted on the side of the throttle body opposite the throttle lever assembly. Its function is to sense the current throttle valve position and relay that information to the control module. TP sensor information allows the control module to generate the required injector control signals (base pulse).

If the TP sensor senses a Wide Open Throttle (WOT) when the engine is operating, a voltage signal indicating this condition is sent to the control module. The control module then increases the injector base pulse width, permitting increased fuel flow.

OPERATION
As the throttle valve rotates in response to movement of the accelerator pedal, the throttle shaft transfers this rotation movement to the TP sensor. A potentiometer (variable resistor) within the Throttle Position (TP) sensor assembly changes its resistance in proportion to throttle movement.

By applying a reference voltage (5.0 volts) to the TP signal input, a varying voltage (reflecting throttle position) is available at the TP output. For example, approximately 2.5 volts results from a 50% throttle valve opening (depending on TP calibration). The voltage output from the TP assembly is routed to the control module for use in determining throttle position.