CVT CONTROL SYSTEM: Primary Speed Sensor

The primary speed sensor is included in the control valve assembly.
The primary speed sensor detects the primary pulley revolution speed and sends a signal to the TCM.
The primary speed sensor generates the ON-OFF pulse (short waveform) in proportion to the rotating body speed which is "The higher the rotating body speed is, the faster the change cycle is". The TCM judges the rotating speed from the changing cycle of this pulse signal.

Fig 1: Identifying Primary Speed Sensor System Diagram & Waveform
Courtesy of NISSAN NORTH AMERICA, INC.