Since in essence only the electrical interface is different, but the sensor measures the same thing, it should be possible to make a cheap interface circuit to interface the voltage-output sensor to the resistance-sensing input of the ECU.

I'm in a bad shape now as I've already bought the "universal" $49 O2 sensor and it's patiently waiting on the shelf.

What I'm probably going to do is to pull it out of the car (the one that I have seems to be still working, although it's lagging), connect it to a power supply to heat it up, and measure its resistance while spraying some CO2 from a can around it. If it works the resistance should change. And there should be no voltage output from it at all -- that so far seems the case, as when I disconnected the sensor from the ECU it read a steady 0.00V. So it may be just true that it's a resistance-output sensor in Regina.

Alas, there's a rather trivial op-amp based circuit to change voltage into "virtual resistance". I will investigate and post my findings with some photo documentation. I also have (the long overdue) LED-overhaul of $7 instrument backlight bulbs docs waiting to be finished.

At last something a (sudo) electrical-engineer would be happy with :)

At least it's less messy once you get the original sensor out to play with.

Cheers, Kuba