Engine light came on, checked codes, Had the following Codes:
P0161 - HO2S Heater Performance, Bank 2 Sensor 2
P0160 - HO2S Insufficient Activity, Bank 2 Sensor 2
P0056 - HO2S Heater Control Circuit, Bank 2 Sensor 2

I replaced the Bank 2 Sensor 2 Oxygen Sensor (passenger side) and cleared the codes. After running, the engine light came back on after a few minutes... Rechecked codes, following codes still present:
P0161 - HO2S Heater Performance, Bank 2 Sensor 2
P0056 - HO2S Heater Control Circuit, Bank 2 Sensor 2 however the P0161 not present...

I checked the fuses and seemed to be ok, unplugged the battery cable - let sit for a 20 min. - re-started - still comes back with the same 2 codes P0161 and P0056...

Any assistance appreciated...

You'll get a lot more help if you post this up in the proper year CTS Forum ^^^.

Maybe one of our moderators will help and move it - this forum is for meets, get-togethers, chit-chat for a geographic area.

Sounds like you have a vacuum leak, a change in your intake tract, or something has upset your fuel/air ratios.

Now all three codes are back on... Can some one please tell me if I replaced the correct sensor - bank 2 sensor 2 - passenger side???

To all that has viewed this - problem resolved... it helps to replace the correct sensor...