I have searched the internet for catalytic converters for my 1998
I am getting the ODBII code for catalytic converter bank1 being
inefficient - P0420.
Is Bank1 the front? Or must I replace both?
I have read in this group that
420 can be a LOT of things: Cat, O2 sensors, even a clogged vacuum line.
Before you go spending a lot of money on parts, spend a little time
checking things out...
I found a clogged vacuum line after 2 O2 sensors...
OK, I think more info will help...
1998 Legacy Outback
Based on what I have read, it looks like the front O2 sensor is fine,
the rear/post cat O2 sensor could be slowing down.
The "before" O2 sensor slowing would trigger another code, the after
one might not.
I can see the before, I will have to go hunting for the after...
Thanks for the info so far!
Question: Is any welding required to replace the cats? It looks like
I might be able to do this myself with a little ingenuity. I know the
nuts will not be easy, but I would probably choose to crack them off
Cats are usually bolted in, but on Toyotas they may be welded.
If it is a welded system (usually the welded system is from the cat back
to the muffler) you can cut the welds, flare the front pipe or adapt a new
pipe, AFTER placing the clamps on the pipe, of course! and get a universal
cat that will fit.
Most Toyotas (Oh, SNAP! Wrong group!!!) er, Subarus have a y pipe that
comes into the cat and then the rest of the system attaches to that.
Subarus usually have 2 cats, a forward and an aft. Here in Mass we have
what's called 'California emissions', meaning the environuts got a hold of
the legislature and adopted the CA standards. I have an '89 GL Coupe and
when we put the exhaust on we 'skipped' the rear cat. The car passed
emissions with almost new-car readings on one cat! However, if they put
the car oon the lift and you only have one cat you're going to have to add