My check engine light just came on Saturday morning. I took my car to autozone to have the OBD II scan done and it referenced code P0420.


The gentleman from autozone did not recognize this code specifically for Volvo but printed out the code for a domestic vehicle and it stated this
"Catylyst efficiency below threshold"


Does anybody have experience with this code and advice on what I should do? My car has 272,000 and I have not noticed any issues with the drive performance since the light has come on.


Thanks,


paulech

 

I'm dealing with the same code (P0420 translates to Volvo ECM-4801)
https://volvoforums.com/forum/volvo-...ictures-80857/

Have you removed the O2 sensors to check their condition and at your mileage it could also be the cat.
My car also seems to run normal but i can't get rid of the darn code.