Throttle Position Sensors

Throttle Position Sensors
Throttle Position Sensors

Masterparts offers high-quality throttle position sensors for sale.

What does a throttle position sensor do in a car?

The throttle position sensor is an integral part of the modern vehicle’s fuel system. It measures the angle of the throttle’s butterfly valve as the vehicle accelerates and decelerates.

The data is used by the engine control unit (ECU) to determine how much fuel to deliver to enable optimal ignition.

Constant monitoring of the valve’s position allows the ECU to adjust fuel injection timing to coincide with the idling, acceleration and deceleration of the engine.

In most cars, the sensor is mounted on the throttle housing between the air filter and intake manifold.

See Spectra Premium for a labelled diagram of an electronic throttle body, including the location of the throttle position sensor, throttle body and throttle control motor.

Throttle position sensors can be one of two types – potentiometer sensors or Hall effect sensors.

Potentiometer sensors provide a variable resistance based on the angle of the throttle valve. Hall effect sensors use a magnetic field to determine the valve’s position.

How does a throttle position sensor work?

The accelerator pedal of the car is connected to the throttle shaft. When the pedal is depressed, a connecting wire moves the shaft and opens the butterfly valve. The opposite occurs as the pedal is released.

The sensor, mounted on the throttle body, detects changes to the angle of the valve. It then transmits an electrical signal to the ECU.

See RX Mechanic for a diagram of an electronic throttle control system.

When the valve is wide open, the maximum intake of air in the engine occurs. At that moment, the sensor transmits an output voltage of around 4.5V to inform the ECU to inject fuel.

Conversely, a voltage of below 0.7V indicates the valve is almost closed. Only a small amount of air is entering the engine.

Based on that signal, the ECU simultaneously adjusts fuel injection to lower the engine’s power output to idle speed.

For a detailed explanation of the throttle position sensor and how it works, see this video by

Signs of a defective throttle position sensor

Engine performance is compromised by a malfunctioning throttle position sensor. It can manifest in a number of ways, from poor acceleration and uneven idling to surging, shuddering and stalling.

The car typically lacks power, fuel consumption increases, and the check engine warning light is on.

Where to get throttle position sensors from Masterparts

We offer door-to-door delivery. Alternatively, visit any of our branches across South Africa or in Windhoek, Namibia.

Throttle position sensors in and around Cape Town:

Throttle position sensors in KwaZulu-Natal:

Throttle position sensors in Namibia:

Masterparts offers a comprehensive range of engine, suspension, steering, braking and electronic parts for thousands of different car makes and models. Contact us if there’s a part you need and we’ll be happy to help.


Call us on 021 657 5757 or complete the form below to get a quote.

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