In the manual, it says this code is either caused by the cat or the secondary o2 sensor. How do I determine which is the culprit and will this cause any hinderance in performance? I tried searching but didn't come up with much on this. The motor is stock, btw. That o2 sensor is expensive as hell and I don't want to replace it if it's not causing the problem. Thanks!

 

Description
This system evaluates the catalyst's capacity by means of the HO2S (Primary Oxygen Sensor and Secondary Oxygen Sensor) output during stable driving conditions. If deterioration has been detected during two consecutive driving cycles, the MIL comes on and DTC P0420 will be stored.


Possible Cause


TWC (Three Way Catalyst; aka catalytic converter) Deterioration
Exhaust system leakage

 

Thanks for the info.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 96hb &raquo;</TD></TR><TR><TD CLASS="quote">Thanks for the info.</TD></TR></TABLE>

No prob bro, that's what I'm here for.