has anybody had this code? it's on a 2000 nissan Sentra it says catalyst system efficiency below thresh hold(bank1) what does this mean? thanks Randy
code Po420 Nissan Sentra?
Aug 25, 2005
2 Replies
First reply
It means that based on what the sensor in front of the cat sees for o2 content and how that compares to the after cat sensor, the pcm assumes, because how it uses the comparison between the 2 that the cat is not efficiently consuming enough o2 to be working properly. That out…
Read the full reply
Shep is correct. From my OBD-II manual:
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
It is PROBABLY a bad catalytic converter. A cheap fix from an exhaust shop, if you use a universal replacement.
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required