P0420 Help with code please

**jinxeng** · 12-09-2006, 10:04 AM

Hey guys
I have a 2000 Camaro Z28 with about 35k miles

I linked my car with the OBD 2 and got a P04020 code, Catalyst Efficiency Below Thresold (Bank 1)

Does anyone know what that means ? I have yet to so my spark plugs which I will today. 3 Days before the code went up, I seafoamed my car. Any clues ? As always, Thanks

**LS1Formula01** · 12-09-2006, 10:10 AM

A lot of people lately have been getting letters from GM on the catylic converters going out prematurely. Take it up to a GM Service Center and they should replace the cat for nothing.

**autotrix** · 12-09-2006, 11:00 AM

**Hurley711** · 12-09-2006, 11:22 AM

One, or both of your cats are probably bad. That code was for my drivers side cat. When I took it in though both were shot. The dealer is required by law to give you new ones if they are less than 8 years old, or have less than 80k miles on em. My dealer was cool enough to replace my o2s also

**jinxeng** · 12-09-2006, 02:02 PM

Originally Posted by Hurley711

One, or both of your cats are probably bad. That code was for my drivers side cat. When I took it in though both were shot. The dealer is required by law to give you new ones if they are less than 8 years old, or have less than 80k miles on em. My dealer was cool enough to replace my o2s also

i'm gonna try to see if they will replace my cats. thanks for your help

**JonB** · 12-10-2006, 02:01 PM

I would give it a few days and see if it goes away. I had the same code a few weeks back after putting some lucas fuel system cleaner/lube. With in a few miles of driving with it in that code poped up. I cleared it a couple times then it just stoped. Have not had it since.

**Danger731** · 12-10-2006, 03:37 PM

Call your local dealer service dept. Give them the VIN, they'll look it up. If it's part of the "recall" they will replace it free. Unless you have a aftermarket welded exhaust..