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Why Doesn’t Throttle Position Sensor (TPS) Show Full 0-100%?

A common question affecting DauntlessOBD users is why OBD-II Throttle Position Sensor data doesn’t show the full range of 0 to 100%. In most cases, it will show around 10 to 20% on the low end, and 80 to 90% on the high end. These limits tend to vary by vehicle model.

While this limited range is understandably confusing, it is what is being reported by your vehicle, which is conforming to the SAE standard for this parameter. SAE defines PID 11 (Absolute Throttle Position) as a reading of 0 to 100% relative to the reference voltage of the Throttle Position Sensor, which is typically 5.0 Volts. It is common for these sensors to have an actual working range of approximately 0.6 to 4.4 Volts, which would result in a reported range of 12 to 88%.

Other parameters, such as Relative Throttle Position, may be useful in reporting a normalized 0 – 100% range, depending what’s supported by your vehicle model.

Additionally, most vehicles use throttle-by-wire these days, which means that the ECM can control the throttle plate independently from how much you’re pressing on the accelerator pedal, so there may not always be a clear relationship between the two. While the throttle plate position can be what you want for engine diagnostics and data logging, if you want to know what the driver is doing, you should instead use the Accelerator Pedal Position or a similar data stream (if supported by your vehicle and app).

Dauntless OBD app showing example of Accelerator Pedal vs Absolute Throttle Position on a 2016 Toyota Tundra