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The throttle position sensor is the most important sensor in a vehicle’s electronic control system; it is primarily used in the engine’s electronic fuel injection system and in electronically controlled automatic transmission systems. The throttle position sensor is installed at one end of the throttle shaft on the throttle body; it detects or monitors the degree of opening of the throttle as well as the speed of change, and converts the position signal into an electrical signal which is then sent to the electronic control unit. It is used to determine various operating conditions of the engine, thereby controlling different fuel injection amounts and ignition timing. In vehicles equipped with electronically controlled automatic transmissions, the throttle position sensor signal is the primary signal for transmission shifting and torque converter locking. There are two types of throttle position sensors that are widely used today: linear throttle position sensors and Hall element-type throttle position sensors. A linear throttle position sensor can inform the electronic control module (ECM) of the exact throttle opening. Most modern management systems use such sensors, which are installed on the drive shaft of the throttle butterfly valve. It is a 3-wire device, with a 5-volt power line, a ground line, and a variable signal output line located on the middle pin. This signal output is crucial for the vehicle’s performance; any \"blind spot\" in the sliding area of the internal carbon track can lead to \"stalling\" and \"slow response\". This discontinuity can be seen from the oscilloscope waveform, and the operator can mark any fault area indicated by the output voltage within its operating range. A good throttle potentiometer should show: a very low voltage when the throttle is closed, the voltage rising gradually as the throttle opens, and the voltage returning to its initial value when the throttle is closed again. Although the voltage of most throttle position sensors is defined by the manufacturer, most of them are not adjustable. Next, we will explain how to connect and configure an oscilloscope by using a BNC-to-banana plug cable connected to channel 1 of the oscilloscope: the red banana plug is connected to a probe that is plugged into the sensor’s signal output terminal, while the black banana plug is connected to a clip for grounding. Set the oscilloscope channel attenuation to 1X, the vertical scale to 500mV, and the time base to 1S. To prevent interference from spikes, a low-pass filter can be enabled; some oscilloscopes also offer one-click settings for this. Turn on the ignition switch; the engine does not start. Slowly move the throttle from the closed position to the fully open position, and then back to the closed position. Slowly repeat this process several times. Some vehicles have two throttle position sensors. One is for engine control, and the other is for transmission control. The signal from the engine throttle position sensor corresponds to the operation of the transmission throttle position sensor. The signals from these two throttle position sensors are opposite to each other, serving to verify one another; we refer to this design pattern as a \"redundant\" design.