Ignite Engine Power The Essential Bank 1 Sensor 1 O2 Sensor Upgrade

The code reader is telling me that this is the "Bank 1 Sensor 2" O2 sensor. Just trying to confirm that the Bank 1 Sensor 2 is also known as the Downstream ... Nifeida 13474 Oxygen Sensor OE Fitment O2 Sensor 1 Sensor 2 Upstream Downstream Auto Parts Fit 234-4018 AFS106 Replacement For Buick, Cadillac, Ponti. 7th Generation Maxima (2009-2015) - Oxygen Sensor Bank 1 Sensor 1 Removal - Well I keep getting the infamous P0420 (Catalyst Efficiency Low ... Im debating if its the O2 sensors or the exhaust? Is there anyway to really tell? Any help would be appreciated. Thanks! Active Member ... Sensor 1 is the first O2 sensor down the exhaust from the manifold, so very close to the front of the car. Ignore the Bank 1 ... Change the sensor and clear the codes. Check for the B1S1 sensor to alternate up and down pretty regularly. B1S2 should be pretty steady indicating the cat is ... P2A00 Replace upstream A/F bank 1 sensor 1 O2 Sensor · 1. Warm the engine up to operating temperature and then shut off the ignition; · 2. Went on ford parts site and it listed 4 oxygen sensor parts with very little information. Does anyone know which one I need? My bigger concern though are my O2 Sensors and the voltage they are showing; Currently I am getting no voltage readings from my upstream 02 ... It's just below the driver side manifold in the crossover pipe. super easy! That sensor will cause havoc when it goes bad, I had one fatten up ...