I always get a code PO 141 code in cold weather, usually 25 degrees or lower which is O2 heater circuit malfunction [ bank 1, sensor 2]. Can any one fill me in on where these are, their function and the possible problem and maybe some trouble shooting tips........I have a gmc seirra 5.7 L thank you

I always get a code PO 141 code in cold weather, usually 25 degrees or lower which is O2 heater circuit malfunction [ bank 1, sensor 2]. Can any one fill me in on where these are, their function and the possible problem and maybe some trouble shooting tips........I have a gmc seirra 5.7 L thank you

bank 1 sensor 2 is the sensor right before the cat. converter..... try swapping it with the one after the cat. se if the code changes.... If it changes to sensor 3 bank 1, replace it.