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TPS — Throttle Position Sensor

Reads how far the throttle is open — the driver's demand — from 0 (closed) to 1 (wide open).

What it is

The TPS reports throttle-blade position as a fraction from 0 (fully closed) to 1 (wide open). Where MAP measures the result of load in the manifold, TPS measures the request — what the driver is asking for. The two together tell the ECU both intent and effect.

Why it matters

Several control decisions key off throttle position and especially its rate of change:

  • Acceleration enrichment — a fast throttle opening signals a transient that needs extra fuel.
  • Idle control — a near-closed throttle tells the ECU the driver wants idle, so it should take over and hold the target RPM.
  • DFCO — a fully closed throttle at high RPM is the cue to cut fuel for engine braking.

How to tune it

TPS is an input, not a setting. The main thing to understand is the closed and wide-open thresholds: near-closed hands control to idle and arms DFCO; wide-open requests full power (and disables closed-loop).

Rule of thumb

Think of TPS as intent and MAP as outcome. A flat spot on tip-in is a TPS-rate / AE story; a steady-state mixture error is a MAP-cell story.

In the game

Throttle is controlled with W and S. The position feeds the gauges and the control logic in real time.