I've tried uk.rec.cars. maintenance and there were no replies.

GS's car, which he bought with lots of codes from engine ECU, all fixed
except one, by replacement of fuse and correcting incorrect O2
connections.

This is the only one left to fix, but I'm stumped....

He has now has two sensors, both producing P0130 pending fault codes,
but as near I have been able to determine from him - no permanent
codes.

This is the pre-cat sensor and they are 4 pin type. He has a spare...

On the bench I have tested the output of the one which is not presently
installed - just a propane torch heating it up and measuring the
voltage output. It showed 0.5v - at peak. Testing it today, it is
showing a much lower peak voltage.

Then I read there is more than type of O2 sensor

Zirconia with an output of 0.1 to 0.9v

and Titanium with either a 0.1 to 0.9v or 0 to 5v output.

Could anyone confirm which type it should be please?

Today I helped check the O2 loom continuity from sensor to the ECU,
which was OK.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk