Parking sensor fault after battery change

[Hpinfo]

Hello - my first post. 2012 DS5 hybrid4. A friend was in need so I loaned him the car (not my daily driver). While he had it, the ‘low voltage - energy conservation mode’ message came up a couple times, so he changed the battery, and of course didn’t follow the procedure these vehicles demand. Anyway, now that I have the car back, the parking sensors are in default mode. Note that I have a factory Citroen hitch that required coding for the install.

My question is this: Would an improper battery change erase the coding for the hitch, essentially setting it back to original? What is the symptom of a trailer hitch install without proper coding? Does it make the parking sensors go to ‘default’?
Any help is appreciated.

[Paul-R]

No it wouldn't (shouldn't?) affect the presence of towbar electrics. I don't know what the symptom of a system not coded in would be as I coded the towbar ECU into the car as soon as I fitted it to my C5 X7 Tourer. I would imagine that it would mostly work except that you would not get some of the subtle alterations in behaviour such as altering the front to rear brake balance and disengagement of rear parking sensors when connecting up a trailer board.

Was the new battery the correct specification?

EDIT
Did he use the towbar electrics while he had the car? There should be a microswitch in the socket to detect the presence of a plug being inserted. Is it possible this is jammed thus disabling the reversing sensors?