Cel Code P0421

[xchristopha]

Tried just changing the gasket out, but still getting the CEL (cleared it, got CEL again, cleared it, got it again) so I ordered the CAT. Expecting it to arrive Friday.

 

[xchristopha]

New cat is in. No more CEL. Passed emissions tests.

However, an easy job turned out to be frustrating. I had two bolts shear at the base of the flange.

On top of it when I got my new license plate and tried to put it on the two plastic screws that held in the old one also sheared when I tried to remove them. For real.... WTF! Can't remember if these were the ones that came with the car or were part of an aftermarket frame I put on once. Who ever spec'd plastics screws on the exterior of a car was real genius.

 

[Kansei]

plastic screws? mine are metal, and I'm pretty sure gauging by how corroded and craptastic they look that they're oem haha.

 

[TheMAN]

New cat is in. No more CEL. Passed emissions tests.

However, an easy job turned out to be frustrating. I had two bolts shear at the base of the flange.

On top of it when I got my new license plate and tried to put it on the two plastic screws that held in the old one also sheared when I tried to remove them. For real.... WTF! Can't remember if these were the ones that came with the car or were part of an aftermarket frame I put on once. Who ever spec'd plastics screws on the exterior of a car was real genius.

any reason why you didn't have your cat warrantied by the dealer instead of paying for one?

the screws should be reachable at the inside of the trunk

 

[xchristopha]

any reason why you didn't have your cat warrantied by the dealer instead of paying for one?

the screws should be reachable at the inside of the trunk

I didn't even know that the emissions were covered to 80, my warranty for everything else was 3yr 50k I believe. Had I known this could be replaced for free I would have gotten off my butt and done it... just ignorance I guess. I previously lived in an area where they didn't check emissions, so when the light came on it concerned me, but the light would come and go so I dismissed as the car's sensor being fussy to the weather. 20k later I moved and had to get emissions checks so that got me going on getting it fixed.

 

[gjmoreo]

P0421 // Header

Hey Guys .. got a simalar issue.
My Car has thrown the code: P0421 - "Warm Up Catalyse Efficiency Below Threshold (Bank 1)" ..

On the car right now is a MAGNAFLOW catback and a AEM sri .. Im all N/A with this car.
I picked up a Thunder header from this GB --> (still un-installed) http://www.msprotege.com/forum/showthread.php?t=123631351

My question is ... now that im getting this p0421 code .. will this header install fix the problem? In that GB ... Prote states:

As for the Headers, they will come with a built-in CEL eliminator of the type shown on the Mazda 3 header. (See Pic)

http://www.msprotege.com/forum/attachment.php?attachmentid=76014.

I will not guarantee that you won't throw a CEL but none of the 1.6/2.0 headers have had one. My test-fit Mazda 3 header did throw a CEL, though. It's possible that we may eliminate it with a little experimentation but if not, you will need a CEL fix as you would with any other header.

2.0 Header --> http://www.msprotege.com/forum/attachment.php?attachmentid=76002

I want to be able to get good gas mi and run the car as I have been for the past 5 yrs. Now is colder than a mother here in NY and I'd like to fix this CEL issue in the fastiest and easiest way possible .. Please and thank you in advance for anyone that has either done this header install or done this CEL fix already. I'll owe you one ... or two...
(friday) (thinkbeer

 

[Diehonda]

You should be fine. If it throws a CEL use a spark plug non fouler.

 

[thrasher]

that little tube on the midpipe moves the O2 sensor away from the exhaust stream so it will read a temperature similar to what it would after the pre-cat.

If they've added that onto the header it will work fine. It's the same theory as the non-fouler trick.

 

[gjmoreo]

Thanks guys ... Im gonna give it a shot and I'll post what whe dillio is ...

 

[02Silver2.0]

I had my CEL read and the P0421 code came up. I had my protege emissions tested, and it passed with flying colours, im hopeing it's a faulty o2 sensor. If the cat was gone, would it have failed? Im going to have the mazda dealership run the code so they can hopefully pinpoint the problem so I can go out and get the parts myself.

 

[gjmoreo]

header installed and CEL code went away just as Prote said it would with the build in fix. Salute!