P0420
Asked by B_Wolfe Apr 09, 2018 at 10:37 PM about the 2008 Subaru Impreza 2.5i Hatchback
Question type: Maintenance & Repair
So I have a 2008 Subaru impreza that's throwing
the p0420 code. There three lights that came on,
the CEL, the vehicle dynamics control light? And
the cruise control light is flashing. Everything I'm
reading says it's the cat. Converter. How ever a few
people I talked to that had experience with cats.
Said I could try replacing the rear o2 sensor. So I
did that and cleared the codes and around 80
miles the lights came back on. My question is, is
there anything else that would cause this or am I
looking at a bad cat?
6 Answers
Possible bad cat but also it could be a misfire so a tuneup might also be advised. https://www.obd-codes.com/p0420
Can you tell if it was a bad cat? Did you reaplace it and the problem fixed?
SubaruHelp01 answered 5 years ago
did you ever get a fix on this i am having the same problem
It was a bad cat as well as a bad o2 sensor. I had replaced one of the o2 sensors and it didnt work. I took it in to get looked at and the other o2 sensor that i didnt replace was crossthreaded on but the catalytic converter was also bad. Once it was replaced the problem went away. It wasnt cheap either, i believe it ran for around $900 for a brand new cat and install.
SubaruHelp01 answered 5 years ago
Thank you so much for the fast response. I’m a college kid trying to piece together what is wrong with my Subaru. Sorry to bug you but were you getting P2620 and P0420? My dash lit up with the CEL, traction control light and flashing cruise control. I’m figuring we have/had the same problem. Thanks In advance for any light you can shed on helping me to resolve this, it is much appreciated.
SubaruHelp01. I was just getting the p0420 code, the traction control light and the cruise control light are just there to let you know theres an issue. They were both linked to the p0420 code, or so i was told. They were more of just a alert to get your attention. The other code im not sure of. I would research that one on its own, cause your probably looking at a bad catalytic converter plus whatever the other code is.
