P2080 OBD2 error code refers to the Exhaust Gas Temperature Sensor (EGT) number 1 on the side of the engine where cylinder 1 is located and indicates that its circuit has performance problems. The function of the EGT Sensor is to protect the Catalytic Converter from possible damage due to the high temperatures to which it is exposed. And in diesel engines, it is used to determine the regeneration time of the DPF Filter, according to the temperature.
The EGT Sensor is a very heat-sensitive resistor that receives a 5-volt reference and ground signal from the PCM (Powertrain Control Module). It converts the exhaust temperature into a voltage signal which it then sends to the PCM.
If the exhaust temperature is high, the resistance to the ground will show a high voltage. But if there is a lower temperature, the resistor acts accordingly. If the engine has a low voltage, the PCM is responsible for changing the engine timing or fuel ratio in order to maintain a temperature within acceptable parameters.