Hello All!


A while back I posted two threads about my 1999 v70-xc AWD needing a new catalytic converter. Thank you to Klaus & KSG for your replies!!

I finally got the car back to mechanic a few weeks later - just very slow to post here, so much so that I can't append to the original post. :-)

The very reputable indy Volvo mechanic tested the cat and O2 sensors for vacuum leeks and voltage and reset the obd computer. Again as before, we are getting a P0422 obd code. I have used only 93 octane fuel and have kept the car serviced, except for the cat.

I found needing a new cat hard to stomach. So, I took the car to 2 more mechanics. The all say new cat.

So, OK. We need a new cat. Here's where the news goes from bad to terrible. Everyone says the cat will cost around $1000 for the cat; $200 to install. $1200 is out of the question!

I've searched online for a Direct fit cat for my 1999 v70-xc AWD turbo. I can get a Davico for $270 or a DEC for $360.

The indy Volvo mechanic said an aftermarket cat - not universal - will not communicate with the cars' computer, therefore resulting in my check engine light remaining on. Actually, they said the check light would go off for a short period of time but would come back on soon.

I know the XC AWD's are different beast. However, I don't understand! Cats are only manufactured by a few companies. So how can these companies stay in business selling a warrantied cat if the check engine light comes back on in a few hundred miles?

Has anyone installed a Davico or DEC cat on their turbo AWD - or any other cat which solved the long-term problem?

For the fans: fcpgrpton does not have cats for 1999 v70-xc AWD on their web site.


Thank you in Advance!
Robin

Robin,
A cat converter cannot be "serviced", it either works or doesn't. However, a car with only 135K miles is too young to have a dead cat.

The way the engine computer determine cat efficiency is to compare the reading of the exhaust going in (front O2 sensor) to the exhaust coming out (rear O2 sensor). The electrical values of the O2 sensors must be within certain parameters or the computer will signal a fault because you will be polluting the atmosphere too much.

The error does not mean that the cat is bad, it means that the front and rear sensors do not fall within the guidelines. A "bad" cat is usually clogged up so bad that the engine will not rev because it is restricted and exhaust cannot leave the engine - like a potato stuck in the tail pipe.

So long as your car runs fine, the cat should be OK. If most of your driving is around town with very little high speed driving, like tach seldom going over 2000 rpm, your exhaust might be full of water? You live in a damp climate and it is possible. If there is a steep hill not too far away, try this: Let the engine warm up to normal temps. Stop at the begining of the incline and put the gear in L. Floor it! All the way up to 5000rpm. Look in the rearview mirror for water on the pavement or a lot of steam. Careful, you will be going over the speed limit?
If the car won't go past 3-3500 rpm, your cat is clogged.

Can your mechanic tell you what the values are for the front and rear O2 sensors? The front one will vary a little, the rear should stay steady at around .2V
Some people around the world have cleaned the cavity the O2 sensors reside in and put the sensor back in place, which seems to work. Surprising.

I know you are trying to sell this nice car and don't want to invest a lot of money. I don't blame you, I wouldn't either. Tell your mechanic you are not going to buy a new cat, but could he just clean the sensors? By the way, did he install a Bosh sensor up front or a generic one?

Klaus
--
I still miss my 164 and my 854T. Just driving a V70R :)

Klaus, thank you for all info!! I forgot to ask, but based on my cost, I'm fairly sure my O2 sensors are generic.

I took my car back to my local mechanic today (not indy Volvo mechanic). The mechanic tested the O2 sensors as best you described, Klaus. I can't do the up-hill test because I live in central NC, I don't have any good hills to gun it on. But I have noticed from time to time when I ascend the small hills, it hesitates!

He [the mechanic] said he tested the voltage. He said he could not get a consistent reading because the readings are fluctuating on the front and back. So, he says the O2 sensors are in good shape voltage wise. As well, they are clean. There is no vacuum leak. He feels it definitely needs a cat.

If I had found this forum and made my post 3 years when I began having the P0421 & P0422 problems, I probably could have saved my cat.

All of the mechanics kept telling me it was the cat for 3 years. Nine months ago, after my first post, I changed the O2 sensors. But apparently I am 2 years too late.

According to my indy Volvo mechanic, the cats for my particular model are very sensitive. I have been told an after-market cat will not communicate with the obd computer on my 99 XC AWD turbo.

Klaus, do you still feel it is not a bad cat?

Can anyone recommend a functional after-market or re-conditioned Volvo cat or any other solution which will not cost and arm & leg?


Thank you in Advance!
Robin

Update: I just left the very reputable indy Volvo mechanic. He told me that the reason the after-market cats don't function properly on 1999 v70-xc AWDs is because of back pressure b/w the cat and post-cat O2 sensor. If I understood, he said the pressure isn't normalized in an after-market cat as it is in a Volvo brand cat.

Has anyone have any info on this?

I still don't understand why a cat manufactured for my specific Volvo model will not function properly, aftermarket or not.

Any assistance anyone can offer is greatly appreciated!


Thank you!