P0420 Saturn - ware is bank located

Question

the code p 420 showed for a Saturn Ion 3. Is the bank 1 located near the engine or the muffeller

Answer 1

Catalyst sytem low efficiency Bank 1

Apparantly you only have one bank, The 02 sensor that is near the engine is a engine management sensor, the 02 sensor near the catalytic or after the catalytic is a catalytic monitor sensor It is the 02 sensor near the catalytic that report the condition of the catalytic, this can be in response to engine management system such as worn sparkplugs,