I also have the UR high flow cat and get the same code often. I just keep erasing the code when it pops up. There is a few options when trying to get rid of it.
You can try one of these:
http://www.lancershop.com/customer/p...8&cat=0&page=1
There is other brands and designs of these that also may work. Just Google them.
Or you can have a tuner try to disable it in the ECU.
Or you can get a code scanner that has the ability to erase codes and just erase it when it pops up.