[ainarssems]

Well the pressure sensor is a comment n fault not just D3 but they n general for VAG cars. If you have VCDS or similar you can go and check in measuring blocks, if it shows abnormally high pressure then the sensor is faulty. Another common fault for any car is leak either major or slow leak. When the pressure drops below certain level it will stop working. I notice it has not been running for a while which is never good. If there is major leak it will mean air and moisture could be getting it filling up dryer or causing corrosion resistant inside. Even if there is no leak and it has sufficient pressure not using could mean less oil and additive circulation in the system, not conditioning rubber seals, them drying out, developing micro cracks and starting a slow leak. This is more likely on older cars with clutched compressor meaning if Aircon is off there is not refrigerant circulation, less likely on D3 with permanently driven compressor. Don't think there is common fault on D3 with condenser but there can always be exception with it getting damaged or getting corroded from road salt.

First call would be check pressure with VCDS, if it shows very high pressure change pressure sensor, if it shows low pressure take it to Aircon specialist to investigate for leaks