ive replaced my converter and its now throwing code p0420 why is that in saturn ion 06

Question

I recently had my converter replaced and my car is now throwing code p0420 catalytic converter low effiency why is that

Answer 1

P0420 Catalytic below threshold Bank 1

This may be normal , what happens when a new catalytic convertor is installed with less than 100 miles P0420 may set this is due to out gassing of the internal mating surface,, You would need to operate the vehicle for 1 hour at highway speed to correct the condition