CITROEN DS4 Owner's Handbook Manual page 258

Access to the spare wheel
The spare wheel is installed in the boot under
the floor.
Depending on version, the spare wheel may be
a standard size steel or alloy wheel, or for some
countries it is the "space saver" type.
For access to the spare wheel, refer to the
paragraph "Access to the tools" on the previous
page.
Tyre under-infl ation detection
The spare wheel is not fitted with a
sensor. The punctured wheel must
be repaired by a CITROËN dealer or
aqualified workshop.
If your vehicle has an electric parking
brake, only a space saver wheel can be
stowed in the boot.
Taking out the standard wheel
 Unscrew the yellow central bolt.
 Raise the spare wheel towards you from
the rear.
 Take the wheel out of the boot.