The 2011 Chevy Malibu utilizes two oxygen sensors to screen the fumes gas. The Bank 1 sensor is situated on the lower part of the ventilation system at the back of the motor. It is simply above where the complex finishes and the exhaust pipe starts. The Bank 2 sensor is found just after the exhaust system. Assuming you follow the fumes speak up</br> beginning from the back moving towards the front</br> it is just after where the line twists up to the motor. The Bank 1 sensor focuses towards the fire wall and the Bank 2 sensor focuses towards the traveler side of the vehicle. You will require a 22mm wrench or profound well attachment to eliminate them.