Question

P0430 Chevrolet - what o2 sensor do i wanna change first for the po430 code? Try to save alil Money

Answer 1

P0430 Catalytic system low efficiency Bank 2

This might not be a 02 sensor, just a failed catalytic convertor. If you want to save money use a scan tool data. Depending on the scan tool that you use you would be looking at Bank 2 Sensor 2 , The oxygen sensor goes by upstream which are the Sensor 1 this is the engine management sensor, Sensor 2 are the downstream 02 sensor or the catalytic monitor sensor.

 Sensor 2 is the downstream 02 sensor or the catalytic monitor sensor, this 02 sensor report the condition of the catalytic convertor,

 A good catalytic convertor 02 sensor voltage would stay above 650mv.

 A faulty catalytic not only will fall below 650mv. But if Sensor 2 cycles from lean to rich , the catalytic is faulty.