Toyota Estima 1992 If oil level sensor is stuck and pump running constantly what happens to engine?

The engine will overfill w/ oil & your engine will be damaged, if any oil is left in the oil tank under the hood. That is where it is trying to pump from to get to your oil pan.

You can spend $250. for the replacement part @ Toyota + labor or

remove it & clean all contacts & free the float, or

just disconnect the dang thing along w/ the under hood tank.

Then just check the oil level yourself regularly, as U are supposed to just like any other car or truck. (except the Previa's oil dipstick & fill tube is under the drivers seat. Not hard to get at, just what it is)