hi phil, i have the same problem,i thought i had it sorted when it was in a land rover garage, they said it was not a common fault and said it was a birnt wire that led to a yellow relay failur, six quid for relay hundred for fitting it, been out since the problem still there was told earth wires in engine bay right behind the the instramant clocks three earths, cleaned thease up it seemed beter but did it again on moter way when reached 80 mph, going to run earth from battery to earth near ecu try that,defo not going back to garage, stick with this forum save a fortune.