delinquent543

After scanning my car at autozone, i get the code: "P0420 Catalyst System Efficiency Below Threshold (Bank 1)". is there a way to tell if its the cat or the sensor (maybe like a "seat of your pants" feeling?). Does this code only come up from a clogged/malfunctioning cat, or can a dirty/broken o2 sensor cause this too? i asked this in another thread, but i figure this will help others with the same problem too. hopefull daily driving with this code wont be bed for my car, just until i get it fixed

2001NBMZ28

I'd switch the rear 02's side to side, clear the codes, then see if you get P0430 for the passenger side. If it moves it's the 02, if it doesn't it's the cat. Remember the cats are covered for 8yrs/80K.

92SilverSHO

iTrader: (3)

its 90% a cat, if it was an o2, it would set an o2 code, that simple.

slowtealz28

I got the same reading from autozone, took it to my mechanic and he told me it wasn't the o2's it was the car. Now im trying to figure out if I can just buy 2 replacement hi-flow magnaflow cats and have them welded in place (dual cat)

99PontTA

why even bother...unless you need it to pass emissions...it don't mean sqwat...or get o2 sims for the rear and fergit about......or do the diode mod to the rear o2 circuits.