WARNING: This page is about a different car, the 2003 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Heated Oxygen Sensor Troubleshooting Procedure (1 Of 2)
Courtesy of FORD MOTOR CO.
Fig 2: Heated Oxygen Sensor Troubleshooting Procedure (2 Of 2)