CITROËN DS5 Owner's Handbook Manual page 128

Under-inflation alert
The alert is given by the fixed illumination
of this warning lamp, accompanied by
an audible signal, and depending on
equipment, the display of a message.
In the event of a problem on one of the tyres,
the symbol or the message appears, according
to equipment, to identify it.
 Reduce speed, avoid sudden steering
movements or harsh brake applications.
 Stop as soon as it is safe to do so.
 In the event of a puncture, use the
temporary puncture repair kit or the spare
wheel (according to equipment),
or
 if you have a compressor, the one in the
temporary puncture repair kit for example,
check the four tyre pressures when cold,
or
 if it is not possible to check the tyre
pressures at the time, drive carefully at
reduced speed.
The alert is maintained until the tyre or
tyres concerned is reinflated, repaired
or replaced.
The spare wheel (space-saver type or a
steel rim) does not have a sensor.
The loss of pressure detected does not
always lead to visible deformation of the
tyre. Do not rely on just a visual check.
Operating fault
The flashing and then fixed
illumination of the under-inflation
warning lamp accompanied by the
illumination of the "service" warning
lamp indicates a fault with the system.
In this case, monitoring of the tyre pressures is
not assured.
This alert is also displayed when one or
more wheels is not fitted with a sensor
(for example, a space-saver or steel
spare wheel).
Go to a CITROËN dealer or a qualified
workshop to have the system checked or,
following the repair of a puncture, to have the
original wheel, equipped with a sensor, refitted.