Why are the number of pins of automobile sensors different?

This is related to the internal structure of the sensor, the same structure. Different companies must have different designs. For example, sensors that also detect the speed of some parts of automobiles, such as wheel speed sensors, can be divided into magnetic pulse and Hall according to different structures. The external output of magnetic pulse is two-wire system, and Hall's is three-wire system. In addition to design, some companies will set shielding wires outside the signal lines in order to prevent interference. Similarly, if a shielding layer is added to the outside of the magnetic pulse sensor, the external wiring will become three wires, while if one is added to Hall, it will become four wires. There are other sensors, all of which have different types. For example, oxygen sensors have single wire, double wire, three wire, four wire and six wire. I won't list them one by one.