02 sensor on 2006 Nissan Altima

The code that comes up is P0037 heater circuit low Bank 1 Sensor 2

2 answers
IF DIAGNOSIS was paid for , ask your mechanic if he can guarantee that it's correct. What was TESTED as pushrod already asked?
I see someone has already thrown an 02 sensor on it, like everybody does, without testing the circuits going to the sensor!! Find your answer in that statment....