Throttle position sensor (TPS) reading explained

Throttle position (PID 11) is how open the throttle plate is, as a percentage. At idle with your foot off the pedal it should sit near the closed stop (often a few percent, not always a perfect 0). As you press the accelerator it should rise smoothly to a high number at wide-open throttle.

What a healthy trace looks like

• Stable at idle — no random jumps while the car is sitting.
• Smooth climb when you press the pedal in Park (engine running or key-on, depending on the car).
• Back to the idle value when you lift. A throttle that stays at 20% with your foot off is a mechanical or electronic throttle problem, not a “tune.”

When this PID is the fault

Range/performance and circuit codes: P0121, P0122, P0123. Driveability: surge, a high or hunting idle (P0507), hesitation that matches a dead spot in the pedal. Electronic throttle cars may also set manufacturer codes that generic OBD2 will not name — still graph PID 11; a glitch is visible even when the text is generic.

Do not confuse TPS with engine load

Calculated load can be high while throttle is low (climbing a hill in gear). Throttle can be high while load is modest (neutral rev). If they always move 1:1, you are probably in Park. On the road they tell different stories — that is useful for a shake under acceleration.

In MotorBit

Put throttle and load on the same chart. Tap the pedal: throttle should move first. If load and RPM stumble while throttle looks clean, look at misfire, fuel, or airflow — not the pedal sensor.