I thought you might be interested in my conclusions for misbehaving central locking on a X-Type Jaguar. The problems were varied and not constant as to which doors opened or locked. The most common after not opening any from the outside was that the drivers door could not be opened from the inside without manually opening the passenger door first (all doors lock automatically once the car moves). Upon examination of the keys for the car it was found that they were wet with green Verdi Gris on the PC board. After drying with tissue, normal service was resumed. My conclusion was that the problem was caused by my leaving the keys in box above a central heating radiator in the hall causing them to sweat. I had similar problems with a Ford Mondeo a few years ago. I hope this helps someone.