Conflicting O2 sensor errors - pre vs post cat

[Hamsternator]

I've got 4 sensor related error codes on a 2011 E92 BMW 320i that are causing me a bit of a headache -

P112C - O2 sensor pre-cat, line fault (maybe, can't find 100% info on this)
P114C - O2 sensor post cat, fuel trim rich, bank 2
P2196 - O2 sensor signal stuck rich, bank 1 sensor 1 (pre cat)
P2273 - O2 sensor signal stuck rich, bank 2 sensor 2 (post cat)

So it seems I've got two matching pairs of codes effectively, bank 1 pre-cat and bank 2 post-cat, all rich. The trouble is, I'm trying to work through the possibilities in my head and can't figure out where the issue is most likely to be. Have I just got unlucky and have 2 sensors on the blink at once? Or is a fault report from one sensor playing with the ECU and therefore inducing another faulty report from a perfectly good sensor? And if so, which way round would it be? Or perhaps the fact they're all rich indicates an issue elsewhere?

Any assistance from someone smarter than myself would be greatly appreciated.

[E-bmw]

This is only a guess, educated or otherwise, but I would be changing both showing stuck rich as that means they never switch & so are likely to be stuffed.

I stress that this is just my take & what I would be doing as a first pass to rule them out.

If you can get to them it might be worth fully swapping (ie plug and fitting) the pre cat sensors over and then the post cat ones to see if the fault moves or not.

[stevieturbo]

And presumably you've tested the sensors outputs ?

How do the traces look and do they respond as you would expect ?

[mighty kitten]

Is this the direct high pressure injection petrol engine ??

[Hamsternator]

stevieturbo said:

And presumably you've tested the sensors outputs ?

How do the traces look and do they respond as you would expect ?

Ashamedly no, I haven't, and I'm not sure what expected values would be. I will get some live data.

mighty kitten said:

Is this the direct high pressure injection petrol engine ??

Again, sorry my lack of knowledge is showing through and I'm not sure how I would tell?

[mighty kitten]

It looks a bit like a diesel with steel pipes going to the fuel injectors .

[Steve H]

With the greatest of respect, if you don't know if it has direct injection it's fair to say you don't know how to accurately diagnose a fault on the system. Unless you would consider fitting a gas boiler or building a brick wall yourself just because you've seen a youtube video about it I'd suggest that this is better left to someone who does this for a living.

So I don't seem entirely negative or unhelpful, way over half the lambda fault codes on cars relate to fueling issues elsewhere rather than to faults in the sensors themselves.

[Hamsternator]

Steve H said:

With the greatest of respect, if you don't know if it has direct injection it's fair to say you don't know how to accurately diagnose a fault on the system. Unless you would consider fitting a gas boiler or building a brick wall yourself just because you've seen a youtube video about it I'd suggest that this is better left to someone who does this for a living.

So I don't seem entirely negative or unhelpful, way over half the lambda fault codes on cars relate to fueling issues elsewhere rather than to faults in the sensors themselves.

A fair point, I've no doubt this will end up in the hands of a professional. But I've no rush to sort it so I thought it worth a cursory investigation. Not looked at a problem like this before but you are right, it seems this is a lot more complicated than a dodgy electric window!