P0422 ugh

[Bonesxl1100]

Ok so I was hoping this code would go away after I replaced the pcv system and cleaned out the oil pan and replaced gaskets. (Started that thread a few weeks ago).

Anyway, this code popped back up. I've searched the internets and there's just so many varying opinions. I figured I'd start my own thread on it here.

Where would you guys start with this? Obviously I'm really hoping it's not the cat.

2001 v70xc. About 145k miles.

Thanks

[JRL]

145K it could be the CAT, it could be the O2 sensors, it could be nothing!
These cars tend to throw this code when something is a hair off but NOT NECESSARILY REPAIRABLE.
Explanation:
My 2000 V70R has been throwing this for about 25K miles now, (124K total miles). I turn it off and it usually doesn't come back for 2-3 months.
As long as it doesn't come back within a week or two I wouldn't worry about it.
I believe my R did this at about 48K miles because just before I bought it the CAT and both O2 sensors were replaced (under warranty)
It held for 50K miles when it started all over again, it's just one of these cars. It's also a very fast R (stock), faster than all the others I've owned.
I have a low mileage used CAT sitting here but until it's a permanent fault I'm not doing this big job!

[hoonk]

I have heard of people using an extender such as the link below to help prevent convertor codes.

http://www.amazon.com/O2-Sensor-Spac.../dp/B00CZFCPQU

[DYZ]

There isn't enough space above the cat in these cars to put a straight o2 spacer. You'll need one with a 90 degree angle like this one: http://www.amazon.com/gp/product/B00...A2ZDMPK9MICO93

DYZ

[Bonesxl1100]

I've come across this "fix". But isn't it really just masking an actual issue?

[troyhyde]

Ever tightened (or re-tightened I should say) your exhaust manifold nuts? The ears/ends tend to loosen over time and you could have a minor exhaust leak. Could skew the O2 sensors in a manner the ECM cannot correct for.

If you haven't ever re-tightened, be mindful of the torque values. Some expansion is built into the design and you don't want them "tight".

[Antherzoll]

I've come across this "fix". But isn't it really just masking an actual issue?

The other option is possibly a new rear O2, or a new cat... Most people in the tuning world delete the rear O2 because it is only used to diagnose cat efficiency, nothing else.

Ever tightened (or re-tightened I should say) your exhaust manifold nuts? The ears/ends tend to loosen over time and you could have a minor exhaust leak. Could skew the O2 sensors in a manner the ECM cannot correct for.

If you haven't ever re-tightened, be mindful of the torque values. Some expansion is built into the design and you don't want them "tight".

Any exhaust leak upstream of the front O2 will cause running issues and will throw a code, not to mention you would most likely smell it on load. It is possible that there is a leak downstream of the front O2.

[troyhyde]

The other option is possibly a new rear O2, or a new cat... Most people in the tuning world delete the rear O2 because it is only used to diagnose cat efficiency, nothing else.



Any exhaust leak upstream of the front O2 will cause running issues and will throw a code, not to mention you would most likely smell it on load. It is possible that there is a leak downstream of the front O2.

You must have been born lucky, I've never had a tricky problem throw any type of code! A small exhaust leak will likely cause some minor running issues but none of much consequence unless you are sensitive to a car that runs "perfectly" vs one that runs "pretty well". If you get one that runs perfectly, it won't do so for very long, just the nature of multiple and constantly declining sensors and mechanical parts.

It would take a rather large leak to smell anything in the cabin.

The O2's are very close to each other in these cars (post '98 or so), I can't see where you would have a leak between them.

Personally, I'm not one to pitch all the virtues of Seafoam. That said, I have found it rather useful for finding small exhaust leaks. The smoke-show you get after a treatment (especially if you get somebody to rev the engine while your head is in the engine bay) will reveal all leaks...

[Antherzoll]

The O2's are very close to each other in these cars (post '98 or so), I can't see where you would have a leak between them.

The flex joint would be one.

It would take a rather large leak to smell anything in the cabin.

Depends on how sensitive your nose is.

[troyhyde]

Being in Texas there are fewer (or perhaps zero) rot/rust situations with the flex pipe. Owned quite a few 5 cylinder Volvos and never had a bad flex pipe. Had plenty of leaky exhaust manifolds, turbo to downpipe joints, even turbo housings. Situation is certainly different up north or anywhere salty in the winter...

Here's how sensitive my nose is.... When taking an early morning flight, I can tell that it isn't one giant fart I am smelling but 200 tiny farts combined...