argh.............

Here's the short story:

- Error code for bank2 sensor2 - replace 02 sensor. Bought a pair - went to replace the bank 1 sensor 2 O2 sensor, it was stuck. Tried everything and I think I stripped it.
- Took it to a shop today, they got it out with heat, but the threads were beyond repair apparently.
- They put the new 02 sensor in, but had to tack weld and fill with exhaust putty

Cleared the code. Was fine.
Then a new code showed up - P0420 code which means, I think, there's a leak somewhere.

Took a look at it, but was advised that I should replace the cat assembly and put new sensors in. Could they have damaged the sensor? is there a leak possibly were the putty wasn't put?

I was so disappointed as I thought I'd licked this problem.

And kicked myself at the same time - if I'd just left the sensor in to begin with this would have been avoided...

 

Bank 2 sensor 2 would be post-cat, downstream. If you bought a pair of the same, they would both be downstream. So why did you replace bank 1 sensor 1? The sensors are not the same.

Anyway, any good shot should easily be able to install a new bung no time flat. I had two new one fitted to by BMW to make replacements easier. $70 total for both.Just make sure they are not positioned on the lowest (bottom) of the pipe - just incase there is condensation in the pipes. Water can damaged them. Or they can remove the old hung, weld in a new.

 

Sorry that should be bank 1 and 2 sensor 2 - both downstream.

 

So I should find a proper muffler shop and ask them to install a new bung? and/or weld in a new?

 

I would. I am surprised they just did not do that anyway. Maybe even the threads can be saved... hard to say. FYI, if you could not remove it I doubt the threads were stripped by yourself. It was the person who did it before. O2s need to be installed much like spark plugs, firm but not cranked down. Some people crank on them way too much.

 

So im just trying to make sense of this fault.

What could be throwing the code after 02 sensor replacement? And considering how they fixed it....

Could it it be they damaged the sensor when they tack welded an filled with putty?

Could it just be coincidence that it was a bad tank of gas?

Does my MAF need a clean and PCV replaced?


something has to make sense here to begin to diagnose. I don’t this I have bad cats. And this error only appeared after the removal of the 02 sensor.

it has to be the repair....

thoughts on how best to track this down?

 

Yeah, they probably damaged the sensor. Frankly, any shop that would do something like that I would stay away from. You need to get that straightened out to proceed. MAF is easy to clean, just do it if you want. Make sure the wires in it are not corroded or have surface contamination. PCV failure is pretty obvious, from what I have often read when they fail its hard for the engine to even operate correctly. So again, to begin proper diagnoses get the O2 sensors proper and go from there. You can get Walker downstream sensors for like $22 each if you know where to look. Walker usually re-packages Denso.

 

Thanks. I agree that they must have done something to the sensor. I would be able to check with report back with my GAP tool - but that failed this weekend. Must be a Land Rover thing

and these walker downstreams....any hint as to where to look? I’m in Canada, but have easy access to a usps mail adress.

Thanks.

 

So apparently they need to remove the entire passenger side of the pipes to redo the bung - that's about $400+
I think it would be worth it, but now there is no cat efficiency fault - it's a trim fault.

I also pulled this from GAP -

the Bank 1 sensor 1 (passenger side, downstream) is consistently reader "0". Is this a dud sensor?

 

$400 is ridiculous for what is involved. Again the bung installation itself should not run more than $100, period. As I said, I got two done for $70. So $300 to remove and reinstall the exhaust is insane. For an exhaust shop, this is simple work.

At first glance, there is an issue. You typed the bank wrong again, but downstream sensors should effectively look dead. Little to no voltage. I think the cut-off is about .5 volt, above that you get a CE cot cat efficiency. Dont quote me on that value though. What I find odd is one is .7 volt and the other is 0 volt. If the 0 volt is not generating any voltage ever there is probably something wrong with the sensor. If the other is always above .5, you may have a leak or cat failure. But also notice how different your upstream sensors are from each other. These values should fluctuate when at operating temperature so a live graph display will be more useful actually because I am not sure if these are snapshot values of a moment or averages.