05 niss. quest 3.5L trouble code HO2S2 bank 1 from check engine light. the light has been illuminated for months now. will change asap. how will this affect my vehicle the longer it goes on without being changed?

it's the rear sensor behind cat., but what code was it heater circuit, responce, or high/low circuit?
if you know the number of the code it'll help.

you can test out that circuit with a test light connected to the sensor harness connector and just turn key to run pos. and time the light until it goes out.
the test light has to be between the heater wire and the sensor ground wire.
if it lights and stays on for a bit, the circuit is ok and replace the sensor.

the longer you ride like this the more likely your fuel mileage will decrease and other driveability problems could come into play (such as hesitations, and an outside chance of stalling at times). Not to mention increased emissions and, over a very long period, clogged converter.