My 2002 car has a dual exhaust with sensors before and after the cats on each side.
4 sensors in total. All identical so no pre andpost cat differences. Gems management system.
The ecu monitors emissions for each bank of 4 cylinders, so bank1 and bank2. From memory bank 1 is the left hand side with odd number cylinders(1,3,5,7). Bank 2 is the other side with even numbered cylinders (2,4,6,8).
