Parking Brake faulty?

[Tazojla]

So as I was driving home I pulled up to the traffic lights when a message came up saying parking brake faulty, this has happened quite a few times now. I never use auto hold or the parking brake, I've used it 2/3 times when parked on relatively steep inclines but most of the time I just use park on the gear stick. Can anyone shed some insight as to why this is happening and what the cause is? It happened once and the car wouldn't move, it engaged the brake its self, restarted the car and it was fine. Most of the time I just get the message through iDrive when stationary and it's becoming a bit of a nuisance.

Cheers