Throttle Position Sensor (TPS)

TPS is a variable resistor mounted on side of throttle body. Sensor receives a 5 volt reference signal from the ECM, and based on throttle position, will allow all or part of this reference signal voltage to ground at the ECM. At closed throttle the resistance of the sensor is high, so the ECM will see a returned voltage of only about .5 volts. As throttle angle increases, resistance decreases and the ECM sees an increasing voltage signal, of up to 5 volts, at wide open throttle. The ECM uses this signal in computations to determine injector pulse width.