When driving In very wet weather the "F" warning comes on and the gears (manual and auto) don't function. Local Auto gearbox specialists won't look at semi automatic and told me to contact the main dealer, who quoted £75 for a diagnostic check and said they would then probably refer to a specialist! The transmission works fine in dry conditions, so I think it is a problem of moisture getting into the electrics or sensors, but I am worried about clocking up big bills for a relatively minor fault.