Join Date: May 2007
Location: About to leave Chicago!
Car: 2003 2.5 4EAT with AWP.
Feedback Score: 0 reviews
I think your mechanic is wrong and whaty he told you is exactly the opposite of reality with our cars (I'm assuming you have an Outback. Year? Miles?)
P0420 is VERY RARELY a failing cat.
It is most commonly a failing oxygen sensor (front Subaru, rear any brand), vacuum leak, exhaust leak or what not.
Search that code on the forums and you'll find plenty of info.
Cats rarely fail without serious mechanical problems, I think your mechanic wants to give you an expensive repair bill.
2003 Outback: "Kaylee". 143,000 and counting.
Basics: Quaker State Ultimate Durability 5W30, PureOne oil filter, Fram air filter, Valvoline Maxlife Dex/Merc ATF, Mobil 1 75W90, Michelin Primacy MXV4.
Mods: Fumoto oil drain valve, Phillips VisionPlus low beams, HIR1 Phillips high beam upgrade, Nokya Hyper Yellow fog lights.
Also: More rust and parking lot scars than I care to think about.