# P0420 Error on 2006 Pathfinder



## drumminlogan (Feb 4, 2012)

So my 2006 pathfinder was stalling in the middle of driving last week. I read about the ECM relay recall and took it to the dealer and they replaced the relay. After that it seemed to drive well and hasn't stalled. However a week later the service engine soon light came on. I checked the error code and it is returning P0420 Catalyst System Efficiency Below Threshold (Bank 1).

I'm not much of a mechanic but I want to be informed and hopefully not have to spend money on replacing the catalytic convertors. Is it just a coincidence that this code would come on a few days after replacing the ECM relay, or are they connected. What could be the issues? Thanks.


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## AzDeez (Oct 11, 2011)

Exatly the same scenario on our 2006 Pathy. Hope this goes somewhere because I am not ready to do a full Cat replacement.


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## IanH (Feb 11, 2003)

Depends...
I used a O2 cheater on my 2004 Lexus w 145K miles, same code, Sensor 2 Cat efficiency.
got rid of the code, 18 months now.
Passed emissions here in Texas, don't know about your state.


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## CPLTECH (Aug 29, 2010)

Have not experienced this myself but, I have seen postings by others that should it be the cats, do not delay in getting them replaced. Reason is that as they break up, the small particles will get sucked into the motor and all that fine grit everywhere means a motor replacement. There are some aftermarket brands that are far less expensive than OEM.

2006 PathFinder


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## Mdl (Apr 23, 2015)

Exact same thing with my Nissan Pathfinder. Broke down, had ECM Relay recall fixed and engine light came on as soon as I drove out of Nissan parking lot... Still has not been fixed and Nissan says that it has nothing to do with the ECM Relay recall....


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