This is the Wife's car. When key turned off whirring noise continues for ages and drains the battery. Doesn't matter if engine hot or cold, or just turn key on then off again, the whirring starts. Is it an electronic fuel pump noise? it is not the fan turning. Can anyone shed some light on this issue? Our mechanic was instructed to sort it out but just said the battery was fine. Not surprised as it was charged up to drive it to his workshop. Alternator doesn't seem to be able to compensate as the car is only used for short runs around town.