Transmission Output Speed Sensor
The output speed sensor is a two-wire magnetic pickup device that generates an AC voltage signal as rotation occurs. It is threaded into the transaxle case and sealed with an "O" ring. See Fig 1 and Fig 2 . The sensor is considered a primary input to the Powertrain/Transmission Control Module (PCM/TCM). The Output Speed Sensor provides information on how fast the output shaft is rotating. As the rear planetary carrier park pawl lugs pass the sensor coil, an AC voltage is generated and sent to the PCM/TCM. See Fig 3 . The PCM/TCM interprets this information as output shaft RPM. The PCM/TCM compares the input and output speed signals to determine the transmission gear ratio, speed ratio error detection CVI calculation. The vehicle speed signal is taken from the Output Speed Sensor. The PCM converts this signal into a pulse per mile signal and sends the vehicle speed message across the communication bus to the Body Control Module (BCM). The BCM sends this signal to the instrument cluster to display vehicle speed to the driver. The vehicle speed signal pulse is roughly 8000 pulses per mile.