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P0420 Catalyst System Efficiency Below Threshold (Bank 1)?!

39K views 9 replies 6 participants last post by  03 CrazyTaxi 
#1 ·
so i was cruiseing home yesterday after work at say 40mph local road 2k rpm not beating on it and my check engine poped on i didnt feel any driveablity difrence so i turned back around and went to get my scann tool from work, pulled a p420 for the cats... now i know usually when i get htis code at work on a customer car the cats are known to go bad... o nthe jeeps at least.... but my car is so far completey stock as far as exhuast. all i currently have it a spt intake.... and ironicly have the coob ap and invidia 3 inch catless dp on the way.... any one goten this code before on an all stocker... some thing common??
 
#2 ·
Has to do with the rear O2 sensor.Maybe the sensor is bad,shorted wire, or unplugged.You car should still be under warrenty right?For the 32 bit ECU cars (All STi's and 06+ WRX) this sensor is kinda important.I would get it fixed soon as ya can.
 
#5 ·
i figured it out its nothing to do with the sensors i probed them all checked out ok and what not,.... i jusr recently added that redline fuel system cleaner to my tank... and i think it dumped all of the crap into the cat and destroyed it i clear the code and it comes back every other tank of gas.... ive seen this happen b4 on the jeeps at my dealer... its ok catless dp this weekndf!!!!!!!!!1
 
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