is it possible to wire a 4 wire lamda, up to a 3 wire plug? ordered a new lambda, and i ordered the wrong one

 

I expect it shouldn't be a problem. A 4-wire has a seperate earth whereas a 3-wire is earthed through it's body. You just need to identify a suitable earthing point.

See here for wiring descriptions..Just Lambda, Suppliers of zirconia and titania lambda sensors by post

 

OK, The sensor i have is a facet 4 wire. 1 is white, 2 is white, 3 is grey and 4 is black. does anyone know how these wires would map to the 3 wire plug i have, and which is the earth. from looking at the link above grey is often the earth. if thats the case which wire do the whites go to , which seems to be the common colour for the heater wire , that just leaves the black. the problem is, subaru have a white wire on their lamda loom but the other two wires don't match anything i can find info on.
might have to send this sensor back and try and source a three wire if no one has any ideas