05 Monte Carlo P0420

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01-21-2009, 10:12 AM

brian99_03

Thread Starter

Join Date: Jan 2009

Posts: 12

05 Monte Carlo P0420

I have a 2005 Monte Carlo and it threw the code 0420. Many have told me that the code means that I need a new cat. Is that the case? Are there any special policies or warranties that may cover my vehicle? Is it possible that its not my cat? Any information would be greatly appreciated.

Thanks,

01-21-2009, 06:07 PM

montecarlomike81

Join Date: Feb 2008

Location:

Posts: 12

RE: 05 Monte Carlo P0420

Hey brian. I have an 2002 monte and that same thing happened to me. Chances are you will need a new cat soon, if you haven't replaced it already. A lot of times the PO420 code will come on if the original Cat is going bad, or you put on an aftermarket exhaust or aftermarket cat. I remember reading up on something about them being a dealer recall, but I'm not sure who to contact or if the recall has expired. I would check with the dealer you purchased the car from.

01-21-2009, 06:45 PM

dustybird3

Monte Of The Month - April 2008

Join Date: Nov 2007

Location: Waco, Tx

Posts: 1,406

RE: 05 Monte Carlo P0420

Quote:

ORIGINAL: montecarlomike81

Hey brian. I have an 2002 monte and that same thing happened to me. Chances are you will need a new cat soon, if you haven't replaced it already. A lot of times the PO420 code will come on if the original Cat is going bad, or you put on an aftermarket exhaust or aftermarket cat. I remember reading up on something about them being a dealer recall, but I'm not sure who to contact or if the recall has expired. I would check with the dealer you purchased the car from.

Yours may fall under this, check your vin#, mine was replaced free at 108,000 miles.
https://montecarloforum.com/m_12459/tm.htm

01-25-2009, 04:27 PM

bowtietech

Join Date: Feb 2008

Location: New York

Posts: 154

RE: 05 Monte Carlo P0420

Catalytic converters are covered for 8 years/80,000 miles under the vehicles emission warranty. The special policy for cat replacement above the8 year/80,000 mile cutoff point applies to 2001-2002 vehicles only.