where is the left bank 02 sensor on a 2005 chevy venture

bank 1 is the rear of engine near firewall(which can be considered left bank aswell) the front is bank 2 or right bank, as a general rule , bank 1 is always the side of the engine that has cylinder #1, good luck , hope this helps

Bank one or left side of engine drivers side also # 1 cylinder. Bank two or right side of engine passenger's side also # 2 cylinder side