2003 Jaguar XJ8 Air Suspension Fault

On this 2003 X350 V8 the "Air Suspension Fault" light comes on from time to time, usually in cold damp weather. It usually disappears when car is left for some hours and may not reappear for weeks. It does not appear in warm weather. It first came on 15 months ago. There seems to be absolutely nothing wrong with the suspension or the air compression system. Possibly a sensor fault? There is quite a bit of chat on the web about this not uncommon problem, but most of it, sadly, is misdirected nonsense from well -meaning people, who, sadly, have no real idea what is causing this problem on such a common basis.

Martin