Code p0138 popped up this morning i checked the one after the cat looks clean no black residue on it like it was bad my question is the code reads bank 1 sensor 2 high voltage is this sensor before the cat???/

 

I moved this thread to the correct section.
FF

 

This is the sensor after the cat. As per the engine code index near the top of this section, P0138 means bank 1 sensor 2 o2 Shorted To Voltage. The sensor is bad on the inside. You won't be able to see the failure point in this case.

 

the engine is 5.9L