I checked my Service CD and found the following:

Quote:
Embedded with the sensing element is the HO2S heater. The heating element heats the sensor to temperatures of 800°C (1400°F). At approximately 300°C (600°F) the engine can enter closed loop operation.
It just heats the tip to that temp, but you can imagine the rest of the sensor gets quite hot as well.

1998 Silver Frost SVT Contour born on...8/28/01[/i]
American Iron Shootout Radial Tire 2 Class Champion, Cecil County Dragway April 20, 2002