Quote Originally Posted by seatbeltpads View Post
Where is Bank 1 Sensor 2 located on a 2004..?? I see one when I open the hood right by the dipstick, is there another one hidden...?

I know on my girlfriends impala the same sensor was on the backside crammed against the firewall....
bank 1 sensor 2 is after the catalytic converter. on any vehicle, bank is the side of the engine, bank 1 is the side of the engine with cyl 1. sensor 1 (whether its bank 1 or bank 2) will always be before cat, sensor 2 (whether bank 1 or bank 2) will always be after (in some case, actually IN the cat) cat. Also, on most newer vehicles, sensor 1 is also referred to as heated O2 or air/fuel ratio sensor