When I drive off after an engine-off stop I hear a faint but distinct sound exactly like the boot door locking or unlocking itself. (It is Fabia Mk3 Estate).  I have puzzled over this for months and read the handbook and tried to work out if it is speed or time related. I am NOT talking about the automatic door locking system which happens very quickly after move off and is loud because it is all doors locking and doors are close to where I sit.

This is faint and pretty surely right at the end of the car and can sometimes take a mile or more to occur if I have got into a crawl from the off.  It is likely speed related rather than time related.

Any ideas please?  I am not complaining or moaning, just to make it clear, but just intrigued.

Many thanks  I shall be pretty narked with myself if it is in the handbook !!!

Is it the boot locking? I think that after you set off the boot locks itself.

 

This is so that if you don't lock the the car then when you are in traffic and stationary no one else can open the boot.

To stop the opportunistic theft from the boot.

 

I know if I drive somewhere to pick someone up they cannot first open the boot without me pushing the dash button.

My car is set up not to self lock the doors after I first start to go.

 

Thanks AG Falco

Thanks for reply.

Very soon after moving off -say first 10 yards - all my doors lock AND the boot.  I know this because It often stops my wife opening the boot to put shopping in.

So the faint far-away clunk after 5 or 10 minutes  OR after I reach 20/25 mph (or whatever) must be  1) the system trying to lock my boot (but NOT my doors) a second time OR 2) the system unlocking my boot (but NOT my doors). And I would know this because the door latch is pretty close to my ear-hole !

How can I find out which it is? How do I access the settings for automatic door locking? Do I get to it thru the infotainment screen? Or what?  A trip to the dealer?

I would like to find out because I don't want my boot unlocked after a few minutes (if that IS what is happening).

I've read the handbook so often I can safely say it is pretty damn poor English and clarity.

I think the tailgate locks make a whine rather than a clunk. (From what I can make out, if properly closed the tailgate is always physically locked and a software state decides if pressing the tailgate button will release it.)

 

There are ventilation bits and pieces at that end of the car (like an outlet to defrost the fuel cap drainage pipe) -- does changing the fan, air con or ventilation mode affect it?

Much more likely to be something to do with heating or cooling,  if you have climate control, there are motorised flaps, and could be one of these opening once engine has warmed a bit (closes when cold to stop you getting icy blast)

 

Other possibilities include switches on heated mirrors/rear windows turning off if hot enough etc.  Air conditioner compressors cutting in (also used for demisting), the electric fan in engine

 

There are a few (thermostatically controlled) things that happen in background on modern cars, that you might hear “clunk” occasionally.  Could be any of above after 5-10 minutes depending on outside temperature 

Excellent info. Thank you very much.

I am going to drive round the block which will activate central locking and then get out to see if I can open my boot.   NO NO NO .  I'm going to drive round the block to lock everything then get my wife who has been standing in the street to try to open the boot. It should still be locked if I don't open a door.  But I will drive far enough for the faint clunk to happen or it will not show whether the faint clunk is the boot unlocking or not. If the boot is still locked after the faint clunk I will be quite happy that I will not get a traffic light robbery. And put it down to your excellent suggestions. Thank you.

Whichever you do, H-I-M, I'd give Mrs H-I-M the spare keys so she can let you out ?