CITROËN DS 4 Handbook page 74

Lost keys, remote control, electronic key
Visit a CITROËN dealer with the vehicle's registration certificate, your personal identification documents and if possible, the label bearing
the key code.
The CITROËN dealer will be able to retrieve the key code and the transponder code required to order a new key.
Remote control
The high frequency remote control is a sensitive system; do not operate it while it is in your pocket as there is a possibility that it may unlock
the vehicle, without you being aware of it.
Do not repeatedly press the buttons of your remote control out of range and out of sight of your vehicle. You run the risk of stopping it from
working and the remote control would have to be reinitialised.
The remote control does not operate when the key is in the ignition, even when the ignition is switched off.
Locking the vehicle
Driving with the doors locked may make access to the passenger compartment by the emergency services more difficult in an emergency.
As a safety precaution (with children on board), remove the key from the ignition or take the electronic key when you leave the vehicle, even
for a short time.
Electrical interference
The Keyless Entry and Starting electronic key may not operate if close to certain electronic devices: telephone, laptop computer, strong
magnetic fields, ...
Anti-theft protection
Do not make any modifications to the electronic engine immobiliser system; this could cause malfunctions.
Don't forget to turn the steering to engage the steering lock.
When purchasing a second-hand vehicle
Have the key codes memorised by a CITROËN dealer, to ensure that the keys in your possession are the only ones which can start
the vehicle.
Do not throw the remote control batteries away, they contain metals which are harmful to the environment.
Take them to an approved collection point.