C3 2005 central locking failure

[C3Pre Own]

I've tried various online remedies including the different permutations suggested when disconnecting the battery, all without success. I now lock the drivers door with the key & the other doors using the key to turn the lock actuators in the door jams before closing them. The car is my daily runner, usually with only me in it so this a nuisance rather than a big issue but I would love to fix this particular problem while I'm doing other work on it to get it ready for an MOT.

What can I try to resolve this?

[GiveMeABreak]

So what are you saying exactly as you haven't stated what does or does not happen?

Does the key fob operate the central locking? If so does it lock and open all doors or just the Driver's door?
Once in he car with engine on, does pressing the locking button on the dash lock / unlock all the doors at each press?

[C3Pre Own]

Good point! The fobs both have new, tested batteries & neither is able to activate the remote locking. The dash button activates the central locking - all locks function. The keys can lock & unlock the drivers door using the physical lock but do nothing for the central locking. Only the drivers door lock can be operated with the keys, the other doors can only be opened by using the internal handle on each door. All of which probably points to a fault in the signal receiving component or between that & the component that the dash button is able to trigger.

[GiveMeABreak]

Your issue probably lies in resynchronising the key fobs then, as there is nothing wrong with the central locking.

As for the 3 non-driver doors, this is a normal function for only the driver's door to be locked with the key. In order to lock the other 3 doors in case of a problem, follow my illustrated guide here on this thread:

https://www.frenchcarforum.co.uk/forum/ ... 95#p582195

If you have replaced the fob batteries the keys need to be resynchronised:

Perform the following operations:

• Put the fob key to be synchronised in position "ignition +".
• Within the next 10 seconds, press one of the fob key buttons.
  [*[Release the fob key button.

The ignition key HF PLIP is synchronised.

Repeat this for the other fob.

Carry out a locking / unlocking test of the vehicle’s doors and tailgate.

[C3Pre Own]

Thanks for all of that Marc but the re-synching hasn't worked. The car battery is now in need of a recharge as the carhas been idle for over a week & is currently sitting on axle stands with no oil in the engine while I await the arrival of a new sump to replace the porous one that is on there just now. After I've done that, replaced the broken rear spring, 2 rear shox & a heatshield nut I'll take a look at the keys again & give an update.

[GiveMeABreak]

A low battery is also a major factor - if this is in a bad state of charge then it will definitely affect electronic systems. I would of mentioned that earlier had I known. Repeat the procedure when you battery is charged up - as the same thing will happen.

[C3Pre Own]

Battery is now charged, the new sump is fitted & the key does everything except operate the remote locking. I've done the re-syncing but that doesn't seem to have done anything. What can I try next?