Throttle Position Sensor: Description and Operation

1. Throttle Position Sensor 2. Throttle Valve:

Throttle Position Sensor:

DESCRIPTION
The non-adjustable Throttle Position Sensor (TPS), 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 Powertrain Control Module (PCM). TPS information allows the PCM to generate the required injector control signals (base pulse).

OPERATION
If the TPS senses a Wide Open Throttle (WOT), a voltage signal indicating this condition is sent to the PCM. The PCM then increases the injector base pulse width, permitting increased fuel flow.
As the throttle valve rotates in response to movement of the accelerator pedal, the throttle shaft transfers this rotation movement to the TPS. A potentiometer (variable resistor) within the throttle position sensor assembly changes its resistance in proportion to throttle movement.

By applying a reference voltage (5.0 volts) to the TPS input, a varying voltage (reflecting throttle position) is available at the TPS output. For example;
The PCM sends 5 volts to the TPS; it receives 2.5 volts back from the TPS. Therefore, the PCM "knows" that the throttle opening is halfway, or 50% (depending on its calibration).