Unlocked my Fiesta put keys in my handbag, put handbag in the front seat and grandson on back seat, closed the door and went round to get in to play with grandson while waiting for his mum and the car had locked itself, should it do this?

Perhaps the lock button got pressed when you put your bag down?  It shouldn't relock if you have opened a door.

Surely it shouldn't lock with the keys in the car?

 

On a 2009 it's probably not keyless so wouldn't know the keys were in the car.

Auto-relock occurs if you don't open a door...so maybe the door-open sensor isn't working.  Do the interior lights come on when you open the door as you'd expect?

I  (well my other half) had this happen on a 2016 A3.

She put her sleeping niece in the baby seat, accidentally pressed the lock button on the keyfob (with the doors open), the keys fell on the back seat, she closed the rear door = car locked itself.

Cue me flying across town with the spare keys before she woke up ... or my rear quarterlight was put through 😮

My guess is that your keyfob could have accidentally been pressed before you closed the door, very easy to do if it's in a bag etc.

On 11/9/2019 at 2:19 PM, Guy Heaton said:

Perhaps the lock button got pressed when you put your bag down?  It shouldn't relock if you have opened a door.

Iirc it's only the drivers door that prevents it locking. 

If you open a passenger door it will happily relock itself.