M104 Engine Front Crankshaft Sensor Purpose
 

Would anyone happen to know if the front crankshaft sensor on a M104.990 engine does anything? I inspected my front sensor and found the wire on the left side fender harness was cracked w/ the grounding touching the metal. However, I don't see it plugged into anything?? The sensor wire is in the bottom of a connector, that has a cap on the top & no plug that plugs into it??
I replaced the sensor w/ a spare I had (first time) for this sensor. I understand that the parts diagram shows a front & rear crankshaft sensor for my car (1993 Benz 300SE).
Any insight is appreciated. Thank you.

Front sensor is camshaft position sensor in all liklihood. I've had an M103 with this wire cut off and no ill effects.

The capped plug you are referring to is a diagnostic plug. (On earlier diesels, it has a tach amp plugged into it). Grounding this wire probably doesn't do any harm unless a scope is plugged in at the time, in which case the scope might become fried.

He's talking about the TDC sender by the harmonic balancer.
It ususally goes to X11 diagnostic socket.

Yes Clark - found out that this is just a tester sensor & does not affect engine performance. The rear crankshaft sensor I discovered is the one that the ECU reads from, as well as the camshaft sensor on the left front top of the engine block. Replaced both & am having the computer relearn the stops & other things that it does during relearn (about 10 trips).

Thanks guys for your assistance.