What is throttle position sensor?

What is throttle position sensor?

The throttle position sensor plays a very important role, directly affecting fuel consumption.

What is throttle position sensor?

The butterfly position sensor is one of the very important automotive sensors. The butterfly position sensor is actually a type of variable that changes according to the throttle position and sends the location information to a computer to process information to optimize the amount of fuel that is sprayed. For vehicles using sequential gearbox, throttle position is also a parameter to help control the gearshift process. When information is transferred to the computer, ECU will use that information to calculate the load level of the engine to adjust the fuel injection time, control ignition angle early, adjust throttle compensation.

Throttle position sensorThrottle position sensor

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Structure of throttle position sensor

In order to understand the structure of this part, we need to know how many types of throttle position sensors to determine exactly. Throttle position sensor has 3 main types: contact type, linear type, Hall type.

For contact type

This type of sensor will use no-load contact (IDL) and auxiliary load contact (PSW) to test whether the engine is idling or running under high load. When the throttle is fully closed, IDL is turned on and the PSW contact turns OFF, at which point the vehicle’s control system will understand that the engine is idling.

If you step on the gas, the IDL will turn OFF and the throttle will open at the specified position. At the same time, the PSW will turn on and the control system (ECU) will identify the engine under heavy load. If in a moderate position, the voltage from the IDL pole through the IDL contactor switches to the mass. At full load position, the voltage from the PSW pole through the PSW switch to the mass.

For linear type

The throttle position sensor will now be constructed by the slider and the electrodes. In particular, the slider will adjust along the resistance. At the VTA pole will gradually increase the voltage proportional to the butterfly’s open position. If the throttle is completely closed, the neutral contact will connect the IDL and E2 terminals. From there, the signal will be pushed to the control box and adjusted to the engine fuel amount. To learn more about linear sensor type, please refer to the diagram of throttle position sensor circuit below.

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Diagram of a throttle position sensor circuitDiagram of a throttle position sensor circuit

For Hall sensors

As the latest modern throttle position sensor, Hall will sense the throttle position change most accurately by magnets. In addition, the Hall effect will generate the output voltage from the terminals VTA 1 and VTA 2. After that, these signals will be transmitted to the control box as a parameter to help calculate the amount of fuel.

Correlation between throttle sensor and pedalCorrelation between throttle sensor and pedal

Common failures for throttle position sensor

The throttle position sensor can be damaged after a period of use, the common error is a broken signal wire that prevents information from being transmitted to the ECU box. Signal cable is either cold or positive. In addition, faults in the information processing circuit also cause failure at throttle position sensor.

Install the butterfly position sensor into the butterfly wingInstall the butterfly position sensor into the butterfly wing

When the throttle position sensor is malfunctioning, the vehicle will have phenomena such as unstable speed, accelerated acceleration, increased fuel consumption many times and increased exhaust gas concentration. To overcome this, drivers need to know how to check the throttle position sensor to determine the cause of the fault.


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How to check throttle position sensor

For contact type

You need to check the IDL contact when the throttle closed is connected to E2. When the accelerator pedal is slightly pressed, the IDL has an interrupt with the E2 pin. If the throttle is more than 50% open, is the PSW pin connected to E2?

For linear and hall sensors

First, you need to unplug the power jack and check the sensor pins for components such as 5V power, signal pins, cool pins. When operating the engine, the throttle wing opens, the voltage value at the signal pins must change in proportion to increase and always stable.

According to experience of automotive maintenance experts, the damage is often due to problematic contacts (with the old throttle position sensor). If your vehicle cannot get on the throttle, you need to consider the throttle position sensor because it may be because of this detail that your vehicle has been limited by revs.

Minh Tan

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