2011 XC60 P0420 Code

xyourobob · Post by **xyourobob** » 02 Jan 2021, 11:39

Happy New year to everyone. My 2011 XC60 T6 with 150K miles threw a P0420 code, my hand OBII wouldn't clear the code so I hooked up VIDA and sure enough the ECM fault code "Catalyst System Efficiency Below threshold (bank 1)" was there. Funny enough I was not able to delete the code using VIDA, most times a failing O2 sensor will throw this code and you can clear it and then the code will come on again somewhere in the imminent future but I can't understand why I can't clear it? When I click Erase All I get a communication fault message, car not responding? I'm assuming I will have to purchase a new downstream o2 sensor but can anyone shed any light on why I cannot clear the code?

xyourobob · Post by **xyourobob** » 04 Jan 2021, 13:39

Buzz!!!!

xyourobob · Post by **xyourobob** » 11 Jan 2021, 09:05

I ordered a new sensor for less than $100. It was fun removing the old one, heating it up with a propane torch did the trick. After installing the new sensor I disconnected the battery for 10 minutes to clear the code and so far so the engine light has remained off.

Dzikiewicz · Post by **Dzikiewicz** » 19 Mar 2021, 07:08

I have the exact same car with the exact same code, is this still cleared for you? if you search this code for other P3 Volvos you can see this can be a hole of a problem.