Threw the dreaded P0420 Code (Doh!)

[DiveNut]

Well, looks like a new CAT is in my future. Friggin great, just what I need! Oh well, gonna start my forum search for pros & cons of stock replacement vesus aftermarket versus performance CATs.

[bassplayaz06]

try to trick the ecu first. cheaper and passes inspection. most of the time it wont be the cat that goes bad. though i know mine's gonna go soon.

[scherry2]

boy read that all wrong, 420 code.....

[DiveNut]

Looks like I am going with the universal Magnaflow (part #49205). Found a couple on Ebay ranging from $75-100 w/free shipping. Will have a local shop weld it in. fun fun fun (not)

[DiveNut]

Well after procrastinating for 3 months, I finally bought the new cat and had it installed. Ended up going with a direct fit, Magnaflow piece (part #93200). The local muffler shop knocked it out this morning in 25 minutes while me and my kids waited. Total damage, $222 for the Cat + $75 for the install, $297 total. At least I don't have to stare at that damned CEL now.

[wallyuwl]

You should also replace the intake manifold gasket. If not, you'll have the 0420 code again in a year or at most two. Almost always in these vehicles it is the intake gasket issue that causes the cat to go bad.

[DiveNut]

Quote, originally posted by wallyuwl »You should also replace the intake manifold gasket. If not, you'll have the 0420 code again in a year or at most two. Almost always in these vehicles it is the intake gasket issue that causes the cat to go bad. Have not heard that before. How does the intake manifold gasket kill the cat?Thanks,

[RobK]

i threw the 420 code also...but I just replaced the damn cat with an OEM one last summer!!! Didn't replace the o2 sensors though...just replaced the top sensor yesterday and cleaned the MAF sensor, but still showing the code...

[DiveNut]

Quote, originally posted by RobK »i threw the 420 code also...but I just replaced the damn cat with an OEM one last summer!!! Didn't replace the o2 sensors though...just replaced the top sensor yesterday and cleaned the MAF sensor, but still showing the code...That bites. Did you clear the CEL after the changing O2 sensor?

[RobK]

yeah...pulled the negative wire from the battery...that does it, right? if not, i'm sure auto zone can do it for me...but just for extra info...go to my other topic I have titled "I've just about had it with this car..." and listen to my issues...maybe you can help me with that too...

[offnpublic]

More information on the intake gasket causing this code, please.

[neebishis]

when the intake gasket leaks, you get a lean fuel mix which throws the improper fuel mixture code. It also will cause an intermitent rough idle condition. Its not a difficult repair......there are several threads about it on this site. If you attempt this repair, get your replacement gasket from a Toyota Dealer.....they will have the latest version of the gasket. If they tell you they don't service parts for a Vibe, just tell them you've got an '05 Matrix with the 1.8 engine....that'll satisfy them.

[MarkM04]

Could you see or hear the intake gasket leaking?I have this code too, but I'd like to diagnose it before throwing parts at it.