Engine Speed Sensor: Description and Operation

The PCM receives a signal from the TCM and the transaxle output speed sensor over the bus communication line to indicate vehicle speed on automatic transmission cars. On Manual transmission cars (if equipped) vehicle, a dedicated vehicle speed sensor is connected to the PCM.

The Transmission Control Module (TCM) supplies the road speed and distance traveled inputs to the PCM. From these inputs and the throttle position sensor input, the PCM determines when a deceleration condition occurs.