Bank 1 is on the firewall side.
This sensor is a bit difficult to get to. You will need to remove the coil pack (remove plug wires, remove 4 corner screws, pay attention to connections under some of these screws). You will need an O2 sensor socket and a 3/8 ratchet with slim head. You may want to have a shop do it, as the right wrenchs make a difference. Good luck.
