I have been having problems with P0402 causing the engine light to come on for some time now. I reset it and everything is fine for a while. I have now done two identical trips and the light has come on almost at the same time each trip. It was a round trip of 600 miles on each outward leg no light came on on both return legs the light came on towards the end of the 300 miles when I decided to push on a bit more to get home. The MH is an Autotrail Ducato 3.0 litre 2007 I have replaced the throttle body, miles around 30,000 The engine runs very smooth with no loss of power at any time. Can anyone with experience of this problem give me some idea of what to check.