i had got a service engine soon light come on

then i went to auto zone to get it checked out

and the two codes that came out was

p1168 and p1051

definition of - p1168 - is closed looop control (bank 2)

and then it said

probable cause -

open or short circuit condition
poor electrical connection
failed heated oxygen sensor - bank 1 sensor 1 (H02S11) heater


my question is do i have to change both of them out
and
second is where can i pick up these parts for a fair price with the plug n play connector

where are they located on the car and what is the part number or called

cause i searched and some label them as - front left.. right rear .. ect.

is it the 1 with blue cap connector or green 1 or which color

04 sedan - 120kmiles


all questions and comments is welcome

thanks