Car is pretty much all back together now. Started it up and she started up nice and easy. But there was a CEL. Read the
ECU there were 2 DTCs logged. Both front and rear O2 sensors heater circuits read low. I figured it maybe something to do with the slightly larger
MAF pipe or the 3 Bar MAP sensor? But it was for both HEATER circuits? Weird. Both were plugged in fine.
I have had these codes previously very intermittently before and never got to the bottom of it. Usually it would only happen once in a blue moon, and would clear and not come back. But this was constant.
Had a flick through the wiring diagram to see whats common to both the O2 sensors and the Main relay supplys power to the heater circuit on both sensors. Its a funny relay with 2 sets of contacts. The first set supplys power to all the
ECU controlled components. And the other set power the 02 sensors. And they are the only thing on those contacts.
Popped glove box out found the relay and started testing things and the problem went away. It seams that by disturbing the relay, the issue became intermittent again. Thats a good sign the relay is playing up.
So I wired in a pair of relays in place of the original Main relay. Started up and seams fine?
I hope that sorts the issue. As said ive had it a few times before, but it was never common enough to actually diagnose and fix.