Crankshaft Position Sensor

The crankshaft position sensor is located on the cylinder block rear housing facing the gear teeth (cogs) of the signal plate at end of the crankshaft. It detects the fluctuation of the engine revolution. The sensor consists of a permanent magnet and Hall IC.

When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change.

The changing gap causes the magnetic field near the sensor to change.

Due to the changing magnetic field, the voltage from the sensor changes.

The ECM receives the voltage signal and detects the fluctuation of the engine revolution.

ECM receives the signals as shown in the figure below.

Fig 1: Identifying Crankshaft Position Sensor (POS)

Courtesy of NISSAN NORTH AMERICA, INC.

Fig 2: Camshaft And Crankshaft Position Sensor (PHASE) Signal Waveform

Courtesy of NISSAN NORTH AMERICA, INC.