As the earth travels around the sun in the elliptical orbit it must also be know that the axis of the earth is tilted as well.
So when the earth is at the farthest point and the tilt of the earth's axis is towards the sun in that case the sun rays always incident on the surface of the earth near the poles and hence there is sunlight for the 24 hours of the day. But the intensity of these rays is very low because of the their slanted angle of incident. In other words the same sun rays cover a larger area and the luminous intensity is reduced.
When the earth is near to the sun we have an increased average temperature of the day during that phase giving us an experience of summer season and vice-versa is the condition in winter seasons. The tilt of the earths axis is responsible for variation in extremities of the seasons with respect to the geographical location.
The Celcius and kelvin scale are related unit for unit. One degree unit on the Celcius scale is equivalent to one degree unit on the kelvin scale. The only difference between these two scales is the zero point.
The opposite DTC also comprises of the wiring or ground. If the opposite DTC can be set it is the components that is faulty and if otherwise it is still the components that is faulty