[walt911sc]

The car is a 2001 Sentra with 1.8. The car appears to have two converters so, which one is bank 1? Will code 420 always indicate a bad converter or do the Ox sensors need to be evaluated also?

Thanks,
Walt

 

[saint0421]

VAST majority of the time when this code pops up it's the pre-cat has gone kaput (sp?).

 

[chuckie902]

po420 is for the upper cat
mine did the same thing after a mass air flow meter mishap
pain in the ass to fix too
some places around here in canada wanted ( dealer price $695 and muffler shop was $860 just for part )
i eneded up finding a walker exhaust part for only $340
i will be installing it my self