Vehicles that use fuel injection are equipped with Oxygen Sensors (O2), which are located in the exhaust system, go ahead and behind the Catalytic Converter (TWC). Its objective is to determine the amount of oxygen, to adjust the fuel system and achieve in this way that the air / fuel ratio is adequate; namely, 14.7: 1.
It is worth mentioning that, the O2 sensors (Oxygen Sensor) have a circuit that heats the sensor, in order to shorten the feedback time. Depending on the model, the sensor can use 3 or 4 cables, of which 2 are used for sensor feedback to the PCM (Power Train Control Module). The other two remaining cables cause the heater to power the circuit. As for the earth, if the sensor is 3 cables, it is connected to earth through the exhaust system, but if it is 4 cables, it has a separate cable that provides the ground.
When the diagnostic code P0036 is established, it means that the Oxygen Sensor located after the TWC (Three Way Catalyst) in bank 1, experienced a fault in the circuit of the heating element.