Clutch Volume Index

An important function of the PCM is to monitor Clutch Volume Index (CVI). CVIs represent the volume of fluid needed to compress a clutch pack. The PCM monitors gear ratio changes by monitoring the Input and Output Speed Sensors. The Input or Turbine Speed Sensor sends an electrical signal to the PCM that represents input shaft RPM. The Output Speed Sensor provides the PCM with output shaft speed information. By comparing the two inputs, the PCM can determine transaxle gear position. This is important to the CVI calculation because the PCM determines CVIs by monitoring how long it takes for a gear change to occur.