These lights came on on my d4d recently after driving thru a rain storm. Unfortunately they were accompanied by an engine noise and loss of power. Lights subsequently went off. Noise persisted and could not get over 50kph. Had to be lifted off the motorway. The car is in the shop now for over 4 weeks. All injectors replaced...still no joy....now looking at "the 5th injector ??", whatever that is..Any ideas .