I had a little mishap with a jack and ended up punching a good size hole in my exhaust right on the bend after the first cat. It took a day to get my car into an exhaust shop to patch the hole. In that time I had the “check emission system” & “check parking break” lights come on.

After having the exhaust patched and disconnecting the battery to clear the code, the warning lights returned. The auto parts code reader stated “P0420 Catalyst System Efficiency Below Threshold Bank 1”

Can anybody confirm the “Bank 1” Cat is the one on the head and not downstream?

I am sure the parking brake code is related to the P0420 and will go away once the exhaust issue is fixed.

I am just looking for some help with diagnosing what the actual cause is for the P0420 before taking it to the dealer to get an astronomical quote.

My thinking is maybe I still have a small exhaust leak after the first Cat but before the second o2 sensors.

Or could I have actually damaged my Cat when causing the hole in the exhaust? Any help is appreciated.