On 21 Aug 2018 08:00:03 GMT, Scott Dorsey wrote:

Oh, and I am assuming that your software is correct in enumerating them,
that O2B1S1 is upstream bank one and O2B1S2 is downstream bank one. Make
sure you trust your software either by validating it with a mirror or pulling
a wire from one sensor and making sure it shows up as pulled on the software.

What IS that questionmark? What does it indicate? If you had a plot you
could guess.

Hi Scott,

Thanks for that advice, which is good advice, and which I only received
just now, so I haven't been able to take you up on that test to confirm
what I would have assumed, which is the assumption that...
* O2B1S1 (I would assume is the upstream sensor for bank 1, cylinders 123)
* O2B1S2 (I would assume is the downstream sensor for cylinders 123)

* O2B2S1 (I would assume is the upstream sensor for bank 2, cylinders 456)
* O2B2S2 (I would assume is the downstream sensor for cylinders 456)

I'm not at all sure what you mean by using a "mirror" but it's easy enough
to disconnect a sensor, especially for the two upstream sensors which are
tucked away but accessible from the passenger side of the engine bay.

I have the owners manual for the Cen-Tech Harbor Freight item 60693 OBDII
scan tool, which I had borrowed from a friend. The "G" indicates a "graph"
is available, while the "?" indicates "help" is available.