Throttle Position Sensor (TPS)

The TPS, mounted throttle body, opposite throttle lever, measures throttle valve movement and transmits a voltage signal to ECM. A variable resistor (potentiometer) within the TPS changes its resistance (voltage drop) in relation to throttle position. A Scan tester is used to measure TPS voltage.

A 5-volt reference voltage is supplied to the TPS and a signal circuit transmits dropped voltage to ECM. With ignition on and engine off, TPS voltage signal should be 1.25 volts (throttle closed) or less.