https://docs.emtronaustralia.com.au/transmission-control/wiring/hall-inputs/index.htmlDedicated 2-Wire Hall Effect Inputs The TCM contains 4 dedicated 2-wire hall effect inputs. These inputs are suitable for speed sensors found in many transmissions and ABS systems. Unlike normal digital inputs, they actually provide the sensor with a regulated current source at the system’s battery voltage. When the sensing target passes the sensor, the current draw from the sensor will change. This change in current is used to determine an “edge”.Hugoen-us