I'd probably just clear them and see if the codes return. I suppose the 420 'could' be due to an exhaust leak, particularly if the car was mishandled or took a shock or something???

 

Update:

I took the car to the local Subaru dealer/certified mechanic. They said the catalytic converter was probably bad (P0420) and was probably causing the other IAT/MAP codes (P0113). They then quoted me $1300 to fix the whole thing.

That raised my eyebrow. I'm not the most car savy person, but it seemed to me that issues with the IAT/MAP sensor could affect the cat, but not the other way around. So I took the IAT/MAP sensor off and found that the o-ring was broken. There was noticeable dirt/grime around the inlet where the sensor plugs into the intake manifold. If the o-ring failed, there was a leak and this was causing the codes. If the IAT/MAP isn't sending the correct signals, everything down-line from it would be affected including the cat.

So I cleaned it, threw a new o-ring on it (cost few cents), cleared the codes, and have been driving for a few days now without the engine light returning. It seems to have been the fix.

Kinda boggles me that the mechs didn't even bother to look at the IAT/MAP sensor. But hey, if my fix holds out I'm happy to have saved $1299!

 

This is good!!!!!

See, nothing like looking for the simple first.

 

dealers love the p0420. they can claim the cats are bad and sell you new ones for $1300. along with the new cats you get new o2 sensors wich often is enough to ''fix'' the code. but there are lots of thing that will cause a a p0420 code. see ''cardoc'' posting on the very subject.

 

Thanks!

Here's the link to that thread in case anyone else is interested.

cardoc & P0420

 

Going a bit off topic . . .

I'm wondering how you changed the link to display as cardoc & P0420 instead of http://www.subaruoutback.org/forums/66-problems-maintenance/49537-p0420-diag.html, which is the title for cardoc's (excellent) thread.

I've been trying to find out how to take a link and have it display in different words. (http://www.subaruoutback.org/forums...d-comments-questions-suggestions/49645-how-do-you-change-link-show-subject.html). You seem to have done it. Care to fill me in?