Basically, the DTC code P0161 OBD2 is established when the PowerTrain Control Module (PCM) detects that there is excessive current consumption, or that there is a short circuit in the circuit of the heating element of the Oxygen Sensor (O2). As a result, vehicle emissions tend to increase due to this problem. Specifically, this code refers to the Oxygen Sensor (O2) number 2 which is located in the back of the catalytic converter.