Been searching the forums but didn't see this code mentioned all that much.
My 08 TL Type S with 136K threw this code at me yesterday. O2 Sensors are all original.

Secondary Heat O2 Sensor
(Bank 2, Sensor 2)
Circuit High Voltage

I'm trying to determine which O2 sensor I should replace. I'm not sure which side of the car is Bank 2. Sensor 2 means after the Cat? Do I need an O2 socket? I've replaced O2 sensors on Ford and Dodge cars/trucks but the O2 socket's I have are not 18MM which I think is what this operation calls for... Another question, are there a total of four O2 sensors on this car? Any help/assistance would be great.

 

Well I guess I'll just answer my own post. Turns out it wasn't an O2 Sensor after all. After I located the Bank 2 Sensor 2 O2 location I found one of the wires broken from the harness that plugs into the O2 sensor. Cost about the same as I had my local auto mechanic do the wiring fix who charged 1 hour of labor.