Daughters car with code P0420

[Lyman]

Well my Daughter's car threw a code today It's an 07 Nissan Versa with 73,000 miles. The code is for "catalyst below efficiency thresh hold" So Im thinking it's either an 02 sensor or the CAT.
I just read about the federal emissions warranty and if it's the CAT it sounds like it will be covered. Anyone ever have anything like this covered under the federal emissions warranty? Any other ideas?

 

[eljefino]

My sister's accent had the catco covered under emissions warranty, for an exhaust leak of all things.

Take it in but don't say much, it will be a good experiment of how slimy your dealer is.

 

[The Critic]

If it falls under the guidelines and it is actually a cat failure, then it will be covered.

However, they will likely require you to authorize 1hr of diagnostic time first (About $125-$150) to confirm the problem.

 

[Roadkingnc]

The cat has failed, the code is defined as catalyst below efficency threshold. The mfgr will pay to diagnose the defect. It is federal law to warrant the converter for 8 years or 80k miles, no cost to you.

 

[qr25de]

It's a common code. If you hop onto allsentra.com and search P0420 in the B16 troubleshooting section you will know which O2 sensor to look at.

I HIGHLY doubt that it is the catalytic converter or the pre-cats (Versas have those right?).

 

[Lyman]

I just called the local Nissan dealer. They told me that it's $49 to diagnose the problem. Said if it's a warranty covered repair the $49 will be waved.

So do you guys think it's the CAT? At first I thought it might also be a bad 02 sensor. I read that they should go 100k

 

[dparm]

Bad cat. There are separate codes for the sensor being too high/low.

 

[Lyman]

Thanks for the replies guys. @dparm, That's what I thought but wasn't sure. Im an old carb and distributor guy and these new cars baffle me half the time. Give me my Holley 4bbl and Mallory dual point back.

 

[Colt45ws]

Take it in. Ford replaced both rear converters on my car. I paid zip, though I did have to authorize the diag charge in the case that it wasnt a cat that had failed.

 

[Lyman]

The car is going to the dealer ASAP.

 

[hardcore302]

good luck!

 

[greenjp]

I just had the cat on my 2006 Accord replaced at ~56k under warranty. Same thing, code P0420.

My 2003 Saab with 158k is on the original exhaust, every inch of it. I guess they're on different sides of the distribution.

jeff

 

[JamesBond]

I recently had that code on and off for a few days on a recently purchased high mileage 04 Civic. After an oil change, throttle body spray out, a bottle of Gumout Regane and an Italian tune-up, the code has not come back. Let the dealer diagnose and fix it on their dime, then add some high, rev/high throttle driving as part of your preventative maintenance.

 

[rk1407]

Did you add any fuel additives or injector cleaner lately?

I just added a bottle of fuel injector cleaner to my 2000 Camry and about half way through the tank my check engine light went on with the same code: P0420.

I also noticed my fuel mileage decreased. I usually get 450 miles per tank and I barely got 400 with the injector cleaner. Otherwise, the car feels like it is running the same.

I went to Autozone today and their printout of possible causes say:

1. Air leak in exhaust before rear H20s. (heated oxygen sensor) bank 1

2. AF sensor error.

3. Fuel system fault.

4. Faulty catalytic converter.

I just filled up the gas tank and I am going to run about half a tank of fresh gas through and then reset the check engine light and hopefully the problem will go away.

 

[Lyman]

rk1407 no additives have been added. The only maintenance the car has seen has been OCs with PP since my Daughter has owned it.

 

[Lyman]

Update: My Daughter finally took the car in today after I pestered her for a few weeks. They replaced the cat and upgraded ECU software. NO CHARGE. She paid zip and was a real happy camper. They had it done in 5 hours.

 

[JTK]

That's awesome!

It's unfortunate the infamous P0420 code is such a fickle beast. I've seen vehicles with a few thousand miles on them throw this code, only to go away and not come back. Others have it come/go intermittently, etc.

Problem is once you're out of warranty. A whole CC assembly cost can quickly exceed the value of the vehicle. Hopefully we can keep getting "anti-foulers" for that downstream O2 sensor.

Joel

 

[Dakota1820]

I just had my cat replaced 3 months ago and my light came on for the same code I cleared it and gave it a good drive and hasn't come back in a couple weeks and 500 miles. All the monitors are reading to. Apparently a lot of hshort trips can cause that code because your car never warms up and it is running rich. Keep it in mind if it comes back.