I recently had my front brakes done and the mechanic called to tell me there was a small oil leak coming from the oil feed line the feeds oil into the turbo, so I decided to have that replaced at the same time I had the brakes done. When I picked the car up there was a check engine light on and it ended up being a P0420 catalytic converter code. The car does have 94,000 miles on it, but when I dropped it off there was no check engine light on. Are the oil feed line and recent P0420 code related or is it coincidental? Could the o2 sensor have been damaged in the process?