CITROEN DS4 Owner's Handbook Manual page 219

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 or
repaired.
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.
This alert is also displayed when one or
more wheels is not fitted with a sensor.
In this case, monitoring of the tyre pressures is
not assured.
Have the system checked by a CITROËN
dealer or a qualified workshop.
217
Driving