Throttle Position Sensor: Description and Operation

Voltage Versus Throttle Position Chart:

DESCRIPTION
The Throttle Position (TP) sensor is a potentiometer that is mounted on the throttle body to measure changes in throttle valve angle The Powertrain Control Module (PCM) provides a 5 volt reference signal and a ground to the TP sensor and the sensor returns a signal voltage that changes with throttle valve angle. At closed throttle (close to zero degrees) the TP sensor output signal is low (below 1 volt) and at WOT (approximately 85 degrees) the TP sensor output signal is high (approximately 5 volts).

PCM CORRECTIONS
Because the TP sensor is not adjustable, the PCM must account for build tolerances that could affect the TP sensor output at closed throttle. The PCM uses a learning algorithm so that it can correct for variation of up to six degrees of throttle angle.

PCM INPUT
The PCM uses TP information to modify fuel control based on throttle valve angle. For example, power enrichment occurs when the throttle angle approaches WOT. Acceleration enrichment occurs when the throttle angle increases rapidly (similar to an accelerator pump on a carburetor).

FAULTY TP SENSOR
A faulty TP sensor may cause various driveability conditions and should set a Diagnostic Trouble Code.