shoul the bank 1 sensor 2 air/fuel output around 0.66V or 0.3V?

[98camryberkeley]

My 98 camry show fault P1130 and P0171.
I checked the freeze frame as attached.
And also I check the live data, found that the o2 sensor of bank1 sensor 2 always quite small on ideling. but it can go higher to normal when running.
Could the bank 1 sensor 2 o2 sensor cause P1130 and P0171?
Which one is the sensor 2? is that upstream or downstream?

May I attach a picture? how?

[hill8570]

Sensor 2 is the downstream sensor...and it can't cause either DTC. When idling, it doesn't flip-flop much if at all, which just means that fuel trim is stable and the catalytic converter is handling things well. IIRC, Sensor 2 is usually >0.1V at idle (i.e., very lean, since the catalytic converter is cleaning up pretty much all of the HC coming into it). The voltage you're seeing indicates that either the catalytic converter is becoming inefficient, or the engine is running rich and the cat doesn't have enough oxygen to fully break down the hydrocarbons in the exhaust.