Throttle Position Sensor (TPS)
An engine management sensor that monitors the position of the throttle valve to help the computer regulate fuel delivery and transmission shifting.
The Throttle Position Sensor (TPS) is an electronic sensor mounted to the throttle body shaft. Its primary role is to monitor how far the throttle plate (butterfly valve) is open, which corresponds directly to how hard the driver is pressing the accelerator pedal. It sends this real-time position data as a voltage signal to the engine control module (ECM).
The ECM uses the TPS signal along with inputs from the MAF or MAP sensors to calculate the correct amount of fuel to inject and determine the optimal ignition timing. In automatic vehicles, TPS data also influences transmission shift points and torque converter lock-up.
When a TPS fails or becomes dirty, it transmits incorrect or erratic signals, causing the ECM to miscalculate air intake. Symptoms of a bad TPS include sudden engine stalling, rough idling, hesitation during acceleration, surging, poor fuel economy, and a check engine light. Replacing or cleaning the TPS resolves these driveability issues.