Types of Vehicle Speed Sensors?

[StBrielle]

Vehicle speed sensors are divided into three types: magnetic speed sensors, Hall-type speed sensors, and photoelectric speed sensors. The main functions of the vehicle speed sensor are as follows: 1. The vehicle speedometer displays the driving speed of the car through the swing of a pointer. 2. Simply put, the speedometer contains a system (including a rotating disk with a pointer shaft, a rotating shaft with permanent magnets, bearings, hairsprings, and other components) that controls the swing of the pointer. The swing amplitude of the pointer is ultimately determined by the rotational speed output from the transmission (i.e., the rotating shaft of the speedometer is driven by a flexible shaft, which is connected to the worm gear in the worm-gear transmission pair on the output shaft of the car's transmission or transfer case). 3. Due to the manufacturing process of the components themselves, assembly errors, natural wear during use, and changes in the magnetism of magnetic components, all can cause indication errors in the speedometer.

[DeAxel]

Vehicle speed sensors are mainly divided into three types: magnetic induction, Hall effect, and optical. Magnetic induction sensors are commonly found in older vehicle models, generating electrical pulses by gear rotation cutting magnetic field lines, featuring simple structure and low maintenance cost. Hall effect sensors are currently the most popular, using magnetic targets to trigger Hall elements for digital signal output, often installed at wheel hubs or transmission output shafts. They offer high measurement accuracy and strong anti-interference capability but require additional power supply. Optical sensors are more common in motorcycles, determining rotation speed via LEDs and photosensitive components. When these sensors malfunction, the dashboard speed display may fail, and automatic transmission shifting may become jerky. Ensure compatibility with your vehicle model during selection, as mismatched installation can easily damage circuit modules.

[RowanLee]

In actual vehicle repairs, there are essentially three main types of wheel speed sensors. The magnetic type contains a permanent magnet and a coil inside, generating an AC voltage signal when the vehicle is moving—the higher the speed, the greater the voltage amplitude. Its advantage is that it doesn't require an external power supply, but it has a minimum detectable speed limit. The Hall-effect type is my favorite to repair, as it outputs a square wave pulse signal and can accurately measure even when the car has just started moving. However, it requires an additional 5V power supply. The optical type uses a rotating shutter between a light source and a receiver to generate pulses, but it is particularly sensitive to environmental dust. It's recommended to first check if the wheel speed sensor wiring harness is broken, as corrosion at wire connectors due to winter de-icing agents is a common failure point.

[StAdriana]

Vehicle speed sensors are divided into two types based on installation location: wheel speed sensors and transmission output shaft sensors. Those mounted on the wheel hubs are mostly magnetic or Hall-effect types, generating signals by sensing the toothed ring on the wheel axle for ABS system use. The ones on the transmission are primarily magnetic type, responsible for outputting vehicle speed to the dashboard. Common magnetic sensors are low-cost but prone to failure in low temperatures, while Hall-effect sensors offer high precision and can start from zero speed but are more expensive. When washing the car, avoid directing high-pressure water jets straight at the wheel hub sensor positions, as water ingress can easily cause signal distortion. Different brands have varying locations; Japanese cars often install them on the transmission tail cover, while German cars typically place them beside the wheel hub bearings.