Car opened.

I've often inadvertently locked or unlocked my car when getting the house keys out of the same pocket as the radio key fob.

club hammer on the front bumper for old jaguars IIRC :-) But airbags came along and they were getting too many complaints.

Could you have operated the remote accidentally somehow? When I changed cars, I found myself doing that until I moved the car keys to a separate key ring.

I wounder if you could somehow disable the unlocking part of the central locking system?

Saw the AA do this with a Fiat in the early '90's. Some Italian colleagues had driven over from Rome to work with us, and managed to lock themselves out of the Fiat in the work car park. We all stood around chatting in the car park until the AA turned up, and even then, most of us were paying no attention. One of the Italians screams, at which point we look around. The AA man has just dot a hammer out of the back of his van, and the Italian guy obviously thinks he's about to smash the window, and even we were somewhat puzzled. The AA man reaches under the front wheel arch and taps something with the hammer, and all 4 door lock buttons pop up. Oh, how we laughed...

I know that on some Fords (no idea about other makes), there's a little inertia switch in that area that cuts off the petrol in the case of collision or inversion. I wonder if it would open the doors, too?

Could be that an rf jammer was used to block the remote central lock signal, so as you walked away thinking you'd locked it...

e.g.

Some cars use central locking that is operated with air pressure. Thieves carry half a tennis ball around with them. Never tried it, but it sounds plausible.

In the faint hope of finding one of these systems that still works.

Mine will automatically re-lock if no door is opened within a short period of them being unlocked.

Colin Bignell

A few guesses:- A door /boot/bonnet not always closing properly or at least not reliably operating the associated switches due to wear or maladjustment. Water ingress incl to the locks or through damaged sheathing on cables which flex at the edges of doors.

It might be worth trying to lock the car with a door not fully shut to see whether it locks or just what you should be looking or listening for if it doesn't . Of course if you need to be sure the car is locked you could always pull the CL fuse and do it manually although you would loose the deadlock feature. BTW if you don't normally deadlock it might be worth using it because there might be some faults which may disappear by doing so...

My car (Audi) has an option that locks the car if you unlock it and then don't open any of the doors or boot, so if you accidentally unlock it, it would lock its self again shortly thereafter (takes about 2 minutes I think).

Other features I have set on mine are are auto lock when the car starts moving (it then unlocks when I take the key out the ignition), and selective unlock, so the car will open only the drivers door when you press the unlock on the fob once, for anti-hijack.

Have a look on-line, you can probably get software and a cable to do this yourself, if it is an option or speak to the dealer, or an independent that does BMW programming.

might be a good idea to call the dealer to see if it can be done before you go to the trouble of looking it up and downloading software and buying cables.

Quick look on eBay shows this cable and software suable fro the E39

Also just to add, on mine I have set it to beep when it locks, so I can also hear if it has locked or not when I press the button.

One possibility that has not been mentioned yet: did you buy it second hand? Has the previous owner retained a key?

Another thought: can people record the RF "squawk" that the keys emit? I guess there is some system to foil this. It used to happne with early mobile phones.

Robert

A number of older Citreons suffer from this universal unlocking syndrome. Its either a dodgy contact or crimp connector on those, but I'd have though VW used better parts. Its that old single point of failure issue again. Brian

Hate that, had it turned it off on my car.

That's OK.

The servos and things make enough noise for that indication and of course the indicators flash. I have mine set to beep if it mislocks due to a door not being fully shut.

Someone I used to work with years ago had his XR4i stolen, used as a getaway vehicle, abandoned, and recovered by the police, several times. According the police, yes, hitting it in the right place opened the doors....

(Might have been an XR4x4. It's been a while. I assume security has improved in the meantime.)

there is some system to foil this. It used to happne with early mobile phones.

With very old keys, yes. With newer ones, maybe, for some of them. (It's not a simple replay attack though - those are blocked.)

My S-Max has electric folding door mirrors (we live in an area where they are often vandalised). They also make a good indication of whether the car is locked, although it's pretty audible anyway.

Has the previous owner retained a key?

guess there is some system to foil this. It used to happne with early mobile phones.

Unfortunately yes and for some models the cryptography has been broken. A description of the hardware trick went past in a computer discussion group not long since I think from China. Essentially it grabs the code when you lock the car and knows the next one to use to unlock it.

A secondary and very loud internal motion sensor alarm might help you catch whoever is opening your car illicitly or a Tanyhidden pencam.

Regards, Martin Brown

It's _much_ easier for new "high security" keys. With old radio keys, the tea leaf needed competence. Nowadays they just need a web browser and some bitcoins to order the ready-made gadgetry with.

In the faint hope of finding one of these systems that still works.

In the faint hope of finding the other HALF ? Dave