At present, the commonly used crankshaft position sensors are mainly divided into three categories: magnetoelectric type, Hall type and photoelectric type. 1. The gap between the sensor and the target wheel should be checked first for magnetoelectric type and Hall type. 2. Magnetoelectric type can be used to detect its resistance with a resistance meter, and the resistance value is generally between several hundred and more than one thousand ohms, depending on the vehicle type. You can also start the engine and measure its voltage. The voltage should increase with the increase of engine speed. 3. The Hall sensor can test the power supply voltage first (note: it should be turned on when measuring), and then measure the grounding of the sensor. Finally, measure the signal. The signal voltage should be close to the reference voltage and 0 V. The Hall crankshaft position sensor has three wires, one is the power supply wire (providing the reference voltage), the other is the ground wire and the other is the signal wire. When the sensor works, the signal line will output a square wave signal, the amplitude of the square wave is close to the reference voltage, and the bottom of the square wave is close to 0 V. The higher the engine speed, the greater the frequency of the square wave. Magnetic pulse: DC resistance is 500 ———————————— 2200 Ω. When the iron is close to or far away from it, an AC voltage signal with the amplitude of 1v~ tens of volts is generated. If it is an assembled sensor with magnetic pulse and processing circuit-rare, the measurement method is the same as Hall below. Hall or photoelectric-an active sensor that measures applied voltage, grounding, signal amplitude, waveform, etc. The connection line to the computer board must be detected.