I'm working on a '98 Outback that my scanner says "0420 Catalytic Converter Innefficiency Bank 1". What does "Bank1" mean? It looks like this car has two converters that are in line, but not on the individual banks. Is "Bank 1" telling me which converter it is? I've never worked on Subey this new so I'm a little confused. Thanks for your help.

It is my understanding that the "bank 1" reference has no meaning when applied to a car like yours that only has one exhaust bank, but it would identify which bank in a dual exhaust situation. I would also guess that you may have an O2 sensor issue or a problem with your cat. converter to be getting this code.Bill

likely means that your front 02 sensor has gone sour.

 

Jamie

likely means that your front 02 sensor has gone sour.

 

Jamie

The rear O2 sensor monitors catalyst efficiency.

Is there any way I can test the O2 sensor without actually replacing it first? Possibly testing the resistance across it? Thanks for the responses.

it's defo a cat or 02 sensor

 

really, the only way to know for sure is to go to subaru

have them put the car on the select monitor and diagnose exactly what the issue is....

Is there any way I can test the O2 sensor without actually replacing it first? Possibly testing the resistance across it? Thanks for the responses.

I have read about a technique on the internet involving a propane torch and a voltmeter. I wouldn't trust it as it seems prone to user error. If you are interested I can google it and post a link. If I were you I would buy a universal replacement and do a little soldering. I am pretty sure the rear sensor is a three wire. If you need a hand swing up to Nunda tomorrow afternoon.

it's defo a cat or 02 sensor

 

really, the only way to know for sure is to go to subaru

have them put the car on the select monitor and diagnose exactly what the issue is....

Yep, a scanner capable of reading Subaru should give you cross counts AFAIK, a relative indication of O2 sensor health. For what it costs to drive to Sayre PA or Victor NY and pay a diagnosis fee you could buy two universal replacements.