Multiple CEL's on '08 MS3

[Cool1Net6]

Hey There.

I have a 2008 Mazda MazdaSpeed3 that I bought last summer. I've had the car for about 9 months and have been meticulous about keeping up with maintenance, even doing my own oil changes. Over this time I've had a few CEL codes come up. I've scanned them immediately, but I just wanted a second opinion on what they mean.

Date, Mileage, Code, Description
8/30/10 41537 P0422 Evap Emission Control Sys Leak (Small)
11/3/10 45793 P0422 Evap Emission Control Sys Leak (Small)
12/1/10 47653 P0455 Evap Emission Control Sys Leak (Large)
2/18/11 52700 P0455 Evap Emission Control Sys Leak (Large)

I heard these are mostly "you didn't close the gas tank cover properly", but I wanted another opinion, since they went from Small to Large. Any ideas/suggestions on what else I could check?

 

[boosted1]

P0422 means the ECM (Engine Control Module) believes your catalyst efficiency to be low. If your oxygen sensors are operating normally and you have no exhaust leaks, then you indeed have a catalytic converter problem; you'll need to replace your manifold catalytic converter.


P0455 most likely means one or more of the following has happened:

* A loose or improperly affixed gas cap
* A non-conforming gas cap (i.e. not factory/original brand)
* Other leak or damaged piece in EVAP system

With a p0455, the most common repair is to:

* Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
* Otherwise, replace the gas cap, and/or
* Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a vacuum noise or smell fuel), repair if necessary