CEL - P0421 help

[flyfishnc]

I have a few questions about my cel light which came on a while back. I started repairing the 'issues' to rid myself of this light so I can get the mazdaratti inspected.

First, I had to replace the 'after cat' o2 sensor. Once that was replaced, there was another cel... That code said it was a vacuum leak or a fuel injector problem (P0171?). Anyway, I discovered that my air intake hose was cracked almost in half. After replacing the hose, I now have another code...the P0421.

My question is how do I know which cat to replace? I see there are two on my car; one is $300 and the other is $80... Since this thing has 120,000 miles on it I only want to spend what I have to. Any help is greatly appreciated.

BTW, sorry for the double post (in another forum). I didn't see the P5 specific forum until later in the day today...

 

[slavrenz]

The one you would replace is the front cat (near the exhaust manifold, not the one under the car). If you're looking to get by super cheap, do the nonfouler trick to get rid of your CEL. Do a quick search in the How-To section and you'll see what I'm talking about.

 

[wiley858]

I had the same CEL. I did the non-fouler trick. Costed me about 5 bucks at radio shack if I remember correctly.

 

[flyfishnc]

Thanks for the replies. Do the "How to cure Cel/Mil from removing cat with Non-Fouler" and "How TO: CEL/MIL Eliminator!" accomplish the same thing? The both look pretty easy to do.

 

[i12drivemyMP5]

Thanks for the replies. Do the "How to cure Cel/Mil from removing cat with Non-Fouler" and "How TO: CEL/MIL Eliminator!" accomplish the same thing? The both look pretty easy to do.

Just do the non-fouler method. The other involves cutting and lengthening your o2 sensor wires.