Hi Guys, i was having problems with my turbo, after some checking and plugging in the snap on machine it turns out that my DPF was so clogged up the turbo would not engage because the pressure was too high. I have managed to do a manual re-gen and clear the DPF out, the problem i am having is that the oil temp is saying minus 40. i think that because the ECU is getting the reading of minus 40 degrees the DPF will not re-generate its self. my first thought was that the oil temp gauge was faulty, but i cant seem to find where the oil temp gauge is. i thought it may have been in the oil pressure switch but that only has one wire from it which i think just tells the computer weather the switch is on or off. does anyone know where the oil temperature reading comes from? its a 2006 mazda 3 1.6 diesel. since changing the air flow sensor and cleaning the egr valve out and doing the DPF re-gen it is running alot better and the turbo is engaging as it should. i just dont want the DPF to clog up again so want to get this oil temp reading sorted.

Long story short, how does the car get the oil temp reading?

Apologies for the long post, and thanks in advanced for your help