One: When the electric vehicle has a brush controller without output
1. Set the multimeter to +20 rounds (DC), and first measure the high and low potential of the output signal of the brake lever.
2. If the signal of the brake has a potential change exceeding 4V when the brake is pinched, the brake fault can be eliminated.
3. Then perform circuit analysis with the measured voltage value of the master logic chip according to the commonly used function table of the brush controller, and check whether the value of each chip peripheral device (resistance, capacitance, diode) is the same as the component The markings on the surface are consistent.
4. Finally, check the failure of peripheral devices or integrated circuits. We can eliminate the failure by replacing the devices of the same model.
Two: When the brushless controller of the electric vehicle has no output at all
1. Refer to the main phase inspection and measurement diagram of the brushless motor controller, use a multimeter with DC voltage +50V to detect whether the grid voltage of the 6-channel MOS tube corresponds to the rotation angle of the handle. 
2. If there is no right, it means that the PWM circuit or MOS tube drive circuit in the controller is faulty.
3. Refer to the main phase check diagram of the brushless controller, and measure whether the voltage of the input and output pins of the chip corresponds to the rotation angle of the handle. You can judge which chips are faulty, and replace the same type of chip to eliminate the fault.
Three: When the power supply of the brush controller control part of the electric vehicle is abnormal
1. The internal power supply of the electric vehicle controller generally uses three-terminal stabilized integrated circuits, generally 7805, 7806, 7812, 7815 three-terminal stabilized integrated circuits, and their output voltages are 5V, 6V, 12V, and 15V.
2. Set the multimeter to the DC voltage +20V (DC) position, and place the black and red test leads of the multimeter against the black and red lines of the handle respectively, and observe whether the reading of the multimeter is consistent with the nominal voltage, and their upper and lower voltage differences It should not exceed 0.2V.
3. Otherwise, it means that the internal power supply of the controller is faulty. Generally, the controller with a brush can eliminate the fault by replacing the three-terminal voltage regulator integrated circuit.
Four:When the electric vehicle brushless controller lacks phase
The faults of the power supply and the brake handle of the brushless controller of electric vehicles can be eliminated first by referring to the troubleshooting method of the brushless controller. For the brushless controller, there are also specific failure phenomena, such as lack of phase. The lack of phase in the brushless controller of electric vehicles can be divided into two situations: the main phase lack of phase and the Hall lack of phase.
1. The detection method of the main phase lack of phase can refer to the speed troubleshooting method of the electric vehicle with a brush controller to detect whether the MOS tube is broken down. The MOS tube breakdown of the brushless controller is generally two pairs of upper and lower MOS tubes in a certain phase. Breakdown at the same time, make sure to replace at the same time when replacing. Check the measuring point.
2. The Hall phase lack of the brushless controller of electric vehicles means that the controller cannot recognize the hall signal of the motor.