Crankshaft Sensor. How it works?

[stevepoulter]

Hi All,

I hope someone has some experience with working with crankshaft sensors. I have looked online and I sort of know how they work but I just need someone to confirm my thinking is on the right lines.

I have a 2010 F10 520d.

The crankshaft sensors according to wiring diagrams has 3 pins.

1 Pin is 5v
2 Pin is 5v signal
3 Pin is earth

(Other sensors are similar but with different input values)

From what I understand the crankshaft sensor earth's the signal pin when it is in an ON state, so the signal pin drops to 0v and 5v when OFF.

This ON/OFF state is changed by the magnetic crankshaft wheel cover, when a magnet is sensed or not.

So if this sensor is removed from the engine the signal pin should always show 5v as it is not near a magnet and therefore cannot be on an ON state (0v)

Is this correct? Or is the OFF state 0v

I need the confirmation as it am diagnosing a fault with my car

[MauiM3Mania]

Moved from General BMW Discussion sub-forum.

[MarcoZandrini]

Crankshaft position sensors, as well as cam sensors and wheel speed sensors, are “Hall Effect” (HE) sensors. Basically, the HE is the distortion of a magnetic field that is sensed by a sensor wire. The distortion occurs when an object that contain iron passes through the magnetic field.

[ross1]

Some are inductive sensors