Suburban 1/2 Ton 2WD V8-454 7.4L (1987)
Throttle Position Sensor: Description and Operation
The Throttle Position Sensor (TPS) is connected to the throttle valve shaft in the throttle body unit. The TPS is a potentiometer with one connection to
ground and the other to a ECM 5 volt voltage source. A third wire from the ECM is used to measure the voltage from the TPS. As the throttle angle
changes, so does the TPS voltage output. By monitoring TPS voltage output, the ECM can determine fuel delivery rate based on throttle valve angle.
