Car remote central locking weirdness

Bit of an obscure one, but it has me puzzled.

The oddest thing happened to my car’s (A Citroen Picasso) remote central locking - about two weeks ago, I noticed that after locking the car using the key remote, the action of lifting a specific one of the rear door handles (none of the others) would open it and unlock the entire car.

This has continued to happen consistently for a couple of weeks; as it was already booked in for a service today, I waited to get it looked at (I just didn’t leave any valuables in it).

Now the odd thing is that the problem is not there anymore, since yesterday, when (after being prompted to do so by the dash panel), I replaced the lithium coin cell in the remote key.

It could just be freaky coincidence of course, but it really looks otherwise; it looks as though the car wasn’t locking properly when the signal from the rremote was weak.

Now hold on a minute; I fully realise how improbable that sounds; the locking system will either get a signal and lock the car, or it won’t get a signal and it will do nothing, right? - The idea that a weak signal would cause it to partly lock the car is just absurd, isn’t it.

And yet, the other thing that is really strange is that the ‘clunk’ of the lock operation is now quite definitely very much louder and more positive, since replacing the battery.

I know this thread paints me as a conclusion-jumping idiot, but is there any way at all that a car’s remote locking system could start to do odd things like this when the activating signal starts to fade in strength?

Um, only if the weak battery caused you to push it longer or more than once, and you ‘double clutched’ the locking system by quickly making it lock/unlock/lock…or some combination thereof.

Sometimes this causes the system to lock or unlock doors out of sync…getting part of it hung up in the middle. You were re-locking after the car was just finishing unlocking.

Thanks for the answer, but I don’t think it can be a double-press thing because the remote has separate ‘lock’ and ‘unlock’ buttons.

There’s a little chip in the remote called an ASIC, an Application Specific Integrated Circuit, basically a purpose-built microcontroller with associated RF generation circuitry, etc. Sometimes these things act funny when they aren’t getting enough voltage, so it’s possible it was doing what Philster suggests all on its own, even though you were pushing the correct button only once. That’s all I can think of.