I have that wonderful P0420 code on my 2009 WRX. We have been told it could be one of two things, either the rear O2 sensor or the cats. We replaced rear O2 sensor cleared the code, then one day later the code popped up again. So my assumption is I need new cats. However there is something that had us a little stumped. I have taken notice the last few weeks on when the light turns on and off. The light will shut off with a full tank of gas, the minute I have less than 3/4 of a tank the light turns back on. This has us stumped. I would think the light would just stay on until we fixed the issue.
We are not strangers to the wonders of Subaru codes by any means. This is however our first turbo charged Subaru and I know they can be rather fussy. So has any one else experienced this or is my car just special?
We are not strangers to the wonders of Subaru codes by any means. This is however our first turbo charged Subaru and I know they can be rather fussy. So has any one else experienced this or is my car just special?