Where are the oxygen sensors on a 2008 Toyota Avalon?

On a 2008 Toyota Avalon, there are typically four oxygen sensors: two upstream (pre-catalytic converter) and two downstream (post-catalytic converter). The upstream sensors are located on the exhaust manifolds, while the downstream sensors are positioned after the catalytic converters. To access them, you may need to raise the vehicle and remove some components for easier access. Always consult the vehicle’s service manual for precise locations and procedures.