Bad cat at 110k?

[Anduril]

Wife got a check wallet light today in her Versa, scanned it and got the dreaded P0420. She's still got 3 years before her first required smog check, but the car only has 110k miles on it, has never had a misfire, and doesn't burn a significant amount of oil (1 qt in 5k miles max).

Is this all we can expect out of cats these days? My Camry still has the original cat at 170k despite being one of those oil-drinking 2AZ-FEs, to the point that it made visible smoke before I replaced the engine. Her old Cavalier made it to almost 250k on the original cat.

I've had to replace them on the Mustang and XTerra, but both were due to misfires.

 

[bbhero]

Question I have is if the fuel is running/burning too rich and sending unburnt fuel into the cats downstream??

If it is not from the oil burning part... A unburnt fuel problem maybe??

I'd bet newer vehicles with cats are not as well suited for oil burning circumstance either... like the older ones like my lady's 98 Camry.

 

[Anduril]

Being a 5 year old vehicle you'd think it would set a CEL if it was running rich, especially rich enough to damage something. Can't be too rich as it never gets less than 30 mpg mostly around town and 40+ on the freeway if we can avoid traffic.

 

[bbhero]

May not set off a cel though... Just rich enough long term to cause a issue with the catalytic converter but not enough to actually have a code appear...

That could well need a scan tool to actually see the problem.. looking at both short term and long term fuel trims...

Or it is from burning that oil...

 

[Anduril]

Is 1 qt/5k a lot? It's done that pretty much since new without getting any worse, and from what I've read here, it seems that's normal on newer cars.

 

[slacktide_bitog]

clear the code and see if it comes back

If you do need a new cat, get Walker #84205 if it's the rear cat, or #84101 for the front cat. They are California-legal universal cats (cut and weld). Rock Auto carries both, but you have to search by part number.; they don't show up when searching by year/make/model because they're "universal" parts. You can use them because rust isn't a problem where you are.

Also replace the oxygen sensors along with the converter.

1 quart per 5k is no problem at all.

 

[Anduril]

Can't use "universal" cats here. [Censored]fornia. I was going to replace both O2 sensors before doing anything with the cat because at over 100k I'm sure they're lazy and it might help pick up an mpg orntwo anyways.

 

[slacktide_bitog]

Originally Posted by Anduril
Can't use "universal" cats here. [Censored]fornia. I was going to replace both O2 sensors before doing anything with the cat because at over 100k I'm sure they're lazy and it might help pick up an mpg orntwo anyways.


You can indeed use universal cats as long as they are CARB-approved. Check out California's official aftermarket catalytic converter database. Universal cats show up as approved and appear on the list. They even give you a link to the EO that authorizes them

It seems like the direct fit cats have both of them in one assembly.

 

[DeafBrad]

Are you sure your cat is bad? While the common problem is the cat is bad, there are other reasons for getting a po420. I got a po420 in my van and cleaning out my egr passages fixed that problem.

 

[bbhero]

I agree... That 1 qt per 5,000 miles is not a lot...


Unlike the 98 Camry my lady has that burns through a qt every 3,000 miles typically...


But every motor is different... And possibly a newer motor/catalytic converter may not be as ok with burning oil as one may think... Candidly that just pure speculation on my part obviously.

If you had 0 oil burning issue then it would led one to believe it more than likely was a fuel burning circumstance or maybe a bad oxygen sensor...

Or possibly what deafbrad mentioned above... Certainly could just be that...

I hope whatever it is it is not anything serious...

I had to replace my catalytic converters on my car at 240,000 miles.... $1,550.

 

[Lubener]

CAT failure is a symptom of a another engine issue. I wouldn't be surprised if the new converter has a similiar short life. CATS should practically last the life of the vehicle provided the engine is running correctly.

 

[Andrew1972]

The CAT may be culprit but so can many other things. Code never equals throwing parts, you need diagnosis.

That all being said in my ownership of a 2007 MDX from 2011(84k) they 2020 (200k) I got this particular code 3 times. Guess what I did?

Drove on it turned off within a week or so and cropped back every 3 years.

 

[supton]

Maybe it's worth looking the O2 sensors, make sure they are working properly, and/or looking for other fueling problems? I've heard of O2 sensors getting lazy and "worn out" but it seems like, most of the threads about cat's and P0420, a new cat is what is required.

While it might not be a part with anything moving in it, it is still an item that can break. How or why some give up earlier than others is something I haven't a clue about. You read about some cars going forever with oil burning and whatnot, while someone has one fail at just outside emissions warranty.

Hopefully it's a cheap repair.

 

[ARCOgraphite]

Cat may be good.but requiring a burnofff. Does the car get run hard enough to clean the cat?

You say it is mainly driven around town.

I'd work up to some pretty aggressive WOT "Datona 500" runs on the highway to clean that puppy , er kitty out.

Really. Floored at/near redline in O/D OFF a couple minutes worth in 5-7 second spurts out there in the mix.

Then remove and clean the MAF, and lightly spray the throttle where it seats, cloth wipe. Reassemble.

Make sure you have a low restriction air filter, not a high efficiency one.

If that doesn't work the telltale sensor may be fouled.

Lastly the cat. But Last.

- Ken

 

[GMBoy]

Do the O2 spacer trick, clear the code - done. That buys you plenty of time to consider replacing a C/C. The P0420/430 code sets at a low 10% thresehold of effiecency loss.

 

[ARCOgraphite]

Originally Posted by Anduril
Wife got a check wallet light today in her Versa, scanned it and got the dreaded P0420.


Is this a PZEV?

PZEV should be warranty covered for 15 year / 150,000 miles. in CA smog law.

Look for that PZEV leaf !

 

[supton]

Originally Posted by GMBoy
Do the O2 spacer trick, clear the code - done. That buys you plenty of time to consider replacing a C/C. The P0420/430 code sets at a low 10% thresehold of effiecency loss.


Not sure if the OP can do that in CA? Technically that is illegal everywhere--but I think all other states don't bother with an actual visual inspection. I could be wrong on that, but I suspect most shops aren't going to bother.

Arco might have a point about driving it hard for a bit, blow some carbon out. Can't hurt. Don't see how the air filter comes into play, but what they heck, give her the beans and see if that does anything.

 

[andyd]

Italian tune up. Hold the transmission in 2 and take it for a 10 mile drive at highway speeds. When my 528e failed smog at 300k, I tested the O2 sensor with a volt meter and it flunked. Replaced sensor car passed

PS Poor engine tune is what kills a cat.

 

[CT8]

The code means? What is the cause of the code? diagnosis is the hard part. Is the cause a bad cat? the input and output? "

 

[Anduril]

Got some O2 sensor data last night. Unfortunately, the graph for the rear O2 looks about the same as it did on my Mustang when the cat was rattling and clearly failed. Fuel trims look fine, long term is +/- 3% and short term stayed within that range as well while driving, ignore the high of 20% as that is when I was blipping the throttle at idle.

Still going to try O2 sensors and telling her to drive it hard. Thanks for the tip on the universal replacement, looks like only the front cat is monitored by the O2 sensor so even if the rear is bad, it won't set a CEL. Probably cheaper to have a shop weld in a replacement than to buy the direct-fit piece with both cats myself.