check engine light on

i just bought this car and its great(2000 lgt wg), the check engine light came on so i took it to auto zone and they told me it was a o2 sensor, the code was p0204, bank 1. i was wondering if anybody knows what or which one this would be.

 

are you sure it wasn't p0420? that would be for cat inefficiency. p0204 is "Fuel Injector Circuit Malfunction - #4"

list of subaru trouble codes
http://forums.nasioc.com/forums/archive/index.php/t-736399.html

subaru cel thread, with lots of p0420s
http://forums.nasioc.com/forums/showthread.php?t=298963

 

hey your right.

 

Had the same thing on my 2000 Lgt Sedan, wound up being the cat, but it was at 140K.

Paul