Vehicle Speed Sensor: Description and Operation
PURPOSEVehicle speed sensor 2 provides vehicle road speed information to the ECM. The ECM uses this data to properly determine ignition and fuel delivery curves.
LOCATION
The speed sensor is located in the speedometer assembly.
CONSTRUCTION
It consists of a reed switch and magnetic rotor turned by the speedometer cable. One rotation of the magnetic rotor opens and closes the reed switch four times, producing a digital signal which is converted to vehicle speed by the ECM.
OPERATION
The sensor operates whenever the vehicle is moving with ignition ON. As the transmission rotates, the speed sensor sends a pulsed on/off signal to the ECM.