The automotive knowledge of odometer sensor detection methods, odometer sensors are generally Hall type, with three wires: the power line of about 8 volts, the signal line, and the grounding wire. If the odometer is normal, intermittently grounding the signal line will cause the odometer pointer to swing. Next, let me introduce it to you

Odometer sensor detection method: Principle

Because the diameter of a car wheel is known, the circumference of the wheel is constant.

. From this, it can be calculated how many revolutions the wheels need to make for each mile traveled, and this number remains constant. Therefore, as long as the number of revolutions of the wheels can be automatically accumulated, and then divided by the corresponding number of revolutions per mile, the distance traveled can be obtained. This simple principle has already been discovered by ancient people and has been used. The "Jili Drum Car" is such a device that utilizes the above principles, coupled with a clever mechanism to automatically beat the drum every certain number of revolutions of the wheels. At this time, as long as a dedicated person records it, the mileage traveled can be obtained. This device is very ingenious and can be used regardless of day or night, and it can also be used by blind people, reflecting the intelligence and wisdom of ancient working people in China. However, if no one on the car memorizes the number of drum sounds, the drum car itself cannot accumulate a total of how many miles it has traveled

Odometer sensor detection method: Fault analysis

Determine whether it is a sensor or instrument fault.

. Disconnect the connector of the transmission and turn on the ignition switch. The connector is connected to the brown red channel wire, which is the No. 2 electrode. Use a self-made wire with a plug to extend it, scratch the grounding part of the vehicle body, and input a pulse signal to the instrument. At this time, if the pointer of the speedometer rotates, it indicates that the instrument is normal. The fault occurs on the sensor reed switch tube or magnetic ring. If the pointer of the speedometer does not rotate at this time, it indicates that there is a fault in the instrument or connecting circuit, and the next step of fault identification can be continued. Practice has proven that the method of using virtual scratch wires to create pulse stop signals is effective in determining the location of the fault There is another method that can also be used to check for the above faults. Raise the left front wheel of the car without turning on the ignition switch. Rotate the left front wheel by hand and use a dedicated detection connector V.A.G1598/4 and a multimeter to measure the resistance between electrodes 2 and 3 on the sensor connector. The resistance should swing between 0 and - n. This method is more cumbersome than the previous one