Hey,

A few weeks ago I had one of my o2 sensors go bad. The service engine soon light was on, and I checked the code with a mechanic at a dealership I work at. It was a bad o2 sensor, so I ordered the part from Nissan and a mechanic and I replaced the bad o2 sensor with the new one. We reset the light, and it went off.

Tonight, the light came on again. I haven't checked the code yet, but if it is the same o2 sensor, could it mean that there is a bigger problem? This might be worth bringing it to a dealership, no?