When I lock my Citroen Berlin to van with my key fob it immediately unlocks itself again

L.s, February 2017

the vehicle thinks one or more doors are not ckosed properly. Check all five doors plus the bonnet, though I dont think the Berlingo worries about that.

This may or may not be relevant but looks useful:

http://www.citroenownersclub.co.uk/bsi-reset.html

http://www.justanswer.com/uk-car/4olpq-citroen-berlingo-reg-central-locking-tailgate-door-open.html

http://service.citroen.com/dtt/IFD/AC/documents/en_GB/AIDE/2050/PDF/infodiag159.pdf

xxx, February 2017