CITROEN DS3 Owner's Handbook Manual page 44

Service overdue
For a few seconds after the ignition is switched
on, the spanner flashes to indicate that the
service must be carried out as soon as possible.
Example: the service is overdue
by 300 miles (km).
For a few seconds after the ignition is switched
on, the display indicates:
A few seconds after the ignition is switched
on, the distance recorder resumes its normal
operation. The spanner remains on .
The distance remaining may be
weighted by the time factor, depending
on the driver's driving habits.
Therefore, the spanner may also come
on if you have exceeded the two year
service interval.
Service indicator zero reset
After each service, the service indicator must
be reset to zero.
The procedure for resetting to zero is as
follows:
switch off the ignition,
press and hold the trip distance recorder
zero reset button,
switch on the ignition; the distance recorder
display begins a countdown,
when the display indicates "=0" , release
the button; the spanner disappears.
Following this operation, if you wish to
disconnect the battery, lock the vehicle
and wait at least five minutes for the
zero reset to be taken into account.
Retrieving the service information
You can access the service information at any
time.
Press the trip distance recorder zero reset
button.
The service information is displayed for a
few seconds, then disappears.