The Speed Sensor is used to indicate the speed of the vehicle & for various other handling & braking systems within the vehicle. It also, in a wide variety of vehicles, controls the transmission shift points. Speed sensors are machines used to detect the speed of an object, usually a transport vehicle. They include: Wheel speed sensors ... The Input and Output Speed Sensors are two-wire magnetic pickup devices that generate AC signals as rotation occurs. They are mounted in the left side of the transmission case and are considered primary inputs to the Transmission Control Module (TCM).
The Input Speed Sensor provides information on how fast the input shaft is rotating. As the teeth of the input clutch hub pass by the sensor coil, an AC voltage is generated and sent to the TCM. The TCM interprets this information as input shaft rpm.
The Output Speed Sensor generates an AC signal in a similar fashion, though its coil is excited by rotation of the rear planetary carrier lugs. The TCM interprets this information as output shaft rpm.
The TCM compares the input and output speed signals to determine the following:
•Transmission gear ratio
•Speed ratio error detection
•CVI calculation