The location of the oxygen sensor in Ford vehicles varies depending on the vehicle and engine. Typically, oxygen sensors are located upstream or downstream from the catalytic converter. The sensors measure the level of oxygen in the exhaust system and allow the power control module to adjust the air-to-fuel ratio.
A diagnostic scan of the vehicle designates which sensor bank and sensor may be causing issues. The owner's manual or service manual can be referenced to determine the location of the sensor designated by the computer scan. Some oxygen sensors may require a specific tool to remove and repair, and they are referenced in the appropriate service manual for the vehicle.