Originally Posted by
AndrewMilne
I think that would be Crank Angle Sensor (alternative name for Crank Position Sensor).
To remove the old one and fit the replacement, you need an 8mmspanner (ring is probably better), so this is an essential extra if you carry a spare sensor.
Getting at the crank position sensor is a bit fiddly, so I suggest making sure that you can locate it and get your hand up there and a (ring) spanner onto the securing bolt, before buying the spare (which is pretty expensive, I paid $150).
Cheers,
Andrew