Car

Only if you had very low oil pressure and didn't know it. I suppose if it was leaking and the engine ran out of oil, that would result in serious damage but that's why they put gauges on the car, so you stop the engine before that damage occurs. There's usually quite a bit of warning, but some people keep on driving until it's too late.

Nope. The Engine Computer doesn't monitor oil pressure in any way. The sending unit is strictly to run the warning light and gauge on the dash.

The original question was, would the sending unit cause engine failure. The only way it could be considered a CAUSE of engine failure is if it was leaking, but the same can be said of a valve cover gasket or any other oil leak. The ultimate responsibility rests with the driver who is checking the gauges once in a while, but in a few rare cases the oil leak can be severe and sudden. Those are the ones that get our attention quickly and we stop the engine right away before damage occurs. Slower leaks, such as from a sending unit or seal will take longer to show up. Typically you will see the oil light flicker at idle or when going around a corner. Slower leaks don't usually result in engine problems if the oil level is checked periodically.

Usually not. The most common result of a leaking head gasket is white smoke from the tail pipe from burning coolant. A vacuum leak could cause surging engine speed as the Engine Computer tries to make up for the extra air entering the engine. If you have a loud mechanical knock from low in the engine, that is typically the result of an oil pressure problem caused by, or the result of worn engine bearings.