how do i fix this?

danielc24 · Post by **danielc24** » Sun Oct 21, 2007 1:18 pm

i was going through a drive thru yesterday and my check engine light came on and this is the code i got.

P0420(M) 1/1 Catalytic Converter Efficiency Catalyst 1/1 efficiency below required level.

what does this mean?

kc2005ptgt · Post by **kc2005ptgt** » Sun Oct 21, 2007 1:20 pm

I believe that is your upstream o2 sensor - either going bad, or gone bad, or cat is bad, or... wait till someone more knowledgable gets on... but that's a start!

danielc24 · Post by **danielc24** » Sun Oct 21, 2007 1:21 pm

well i've had horrible gas mileage for a while now and my car seems sluggish taking off.

ZeroChad · Post by **ZeroChad** » Sun Oct 21, 2007 1:25 pm

Sounds like a great excuse to buy one of these
http://www.modernperformance.com/all/ma ... vert.shtml

dblsg · Post by **dblsg** » Sun Oct 21, 2007 4:45 pm

thats the infamous code you get with running with no cat. so either you need a new cat or the downstream sensor might be bad. i had my car with that code for over a year.... i recently installed my cat back on.... and then the damn sensor wires snapped

so i still have that code. car runs fine though.