View Full Version : CEL on a 2000 Outback

02-09-2006, 06:54 PM
okay guys, i'm trying to help out a friend...

he has a 2000 Outback and had a CEL (P04420) for "catalyst system efficency below standard on bank 1"

bank 1 is for the first in line, correct? that makes sense to me, but i wanted to check with you guys first...

02-09-2006, 07:14 PM
Id reset the ECU, and if it comes back then you know you have problems.

02-09-2006, 07:29 PM
Yep, bank one means the one closest to the front of the car.

ie. O2 Sensor Bank 1, Sensor 1 - front sensor
O2 sensor bank 1, sensor 2 - rear sensor

Subaru's don't have 2ndary banks - because the term "bank" in OBD2 speak means "exhaust manifold". Some cars have O2 sensors/cats on each exhaust runner.

The "cat inefficiency" code you are seeing can mean that the O2 reading from sensor 2 (downstream cat) is too similar to the front O2 reading - which means the cat isn't doing it's job.

You don't necessarily need to reset the ECU - if the car still drives ok, run it with the light on. Within a couple of days normal running, if there is no problem, it'll turn off (the CEL).

If it stays on, then you have a couple of options:

1. replace the cat (approx $260 for bolt on replacement that removes cat 1 and replaces cat 2)
2. replace the O2 sensors (approx $100 for universal Bosch)

02-09-2006, 07:40 PM
alright, thanks...that's how i thought it should be read but i wanted to make sure i was correct....so where did you find this bolt on replacement?

02-13-2006, 10:47 AM
www.ecatalyticconvertors.com (http://www.ecatalyticconvertors.com)

or something like that. They're part of the autopartswarehouse.com/partstrain.com website family.