fault code P0195

Hi Everyone glad to join this site , looks like it could be fun ,
asking all you owners for some help

I own a 2002 2.2diesel pt cruiser that I bought with faults

it smoked heavy black smoke and stuck in limp home mode with ecu , I replaced egr valve which has cleared up smoking fault
and now it have a present fault code with car ( not connected to egr )

fault code p0195 engine oil temp sensor circuit malfunction

as you guys already know the diesel doesn't have a oil temperature senor fitted , im just wondering it it reads it through the coolant sensor as a after thought ? or is there a common fault that's gives ecu wrong reading producing this bogus code ?

I googles it and looks like lots of other diesel owners had same problem but no fix

im hoping someone here has had same problem and know of a fix

regards Dean