Crankshaft Angle Sensor

The crankshaft angle sensor monitors engine speed and piston position. The crankshaft angle sensor, which is built into the distributor. Crankshaft angle sensor has a rotor plate and a wave-forming circuit. The rotor plate has 360 small slits to determine crankshaft angle (one slit for each degree of sensor rotation) and 6 or 4 larger slits at 60 (V6) or 90 (4-cyl) degree intervals, to determine engine speed. The signal slit for the No. 1 cylinder is wider than the other 5 or 3 slits to allow ECU to determine TDC for No. 1 cylinder.

When the signal rotor plate passes the space between the Light Emitting Diode (LED) and photo diode, the slits in the signal rotor plate alternately cut the light which is sent to the photo diode from the LED. This causes a pulsating voltage, which is converted into an on-off pulse by the wave-forming circuit and sent to the ECU.