I have a 2007 g35x. My bank 2 sensor 1 has high o2 voltage at around .9v when at idle. Even when the car is not running (just on position), it registers .9v. It does fluctuate up and down while driving and does drop to ~. 4v when letting off the gas.

There are no codes and the fuel trims are about equal on both sides which generally is around 0% for LTFT and - 10% to 10% STFT. The car does not drive rough or misfire. I get about 15mpg with mainly city driving.

Is this normal? I am thinking it's a wiring problem because my front o2s were recently changed along with my injectors. This problem was occurring before the replacements and I've tried switching the o2s from side to side. What should I test next?

 

Did you ever figure your problem out? My Daughter's car is doing the exact same thing but I am getting a P0300 code, which could be unrelated.

 

The voltage discrepancy is cause by Nissan/Infiniti using different voltage ranges for each bank, and it's perfectly normal. One bank will have double or half of each other because the data being reported is what the ECU is translating to OBD format. These sensors are air/fuel sensors and not regular O2 from what I remember.

An indicator that they are good is good short and long term fuel trims.

 

Thanks MistrDough! I was wondering if that was the case but I couldn't find any information about it. That makes a lot of sense because my fuel trims on bank 2 weren't crazy which I was thinking would have been the case if the ECU was trying to get the AF voltage to .45v. I really appreciate the response; this saved me some digging!