CITROEN DS3 Handbook page 124

Reactivation
Press the "ECO OFF" switch again.
The system is active again; this is confirmed
by the switch warning lamp going off,
accompanied by a message in the screen.
The system is reactivated automatically
at every new start using the key.
Operating fault
In the event of a fault with the system, the
"ECO OFF" switch warning lamp flashes then
comes on continuously.
Have it checked by a CITROËN dealer or a
qualified workshop.
In the event of a fault in STOP mode, the
vehicle may stall. All of the instrument panel
warning lamps come on. It is then necessary
to switch off the ignition and start the engine
again using the key.
Maintenance
Before doing anything under the
bonnet, deactivate the Stop & Start
system to avoid any risk of injury
resulting from automatic operation of
START mode.
This system requires a battery with a special
specification and technology (reference
numbers available from a CITROËN dealer or a
qualified workshop).
Fitting a battery not listed by CITROËN
introduces the risk of malfunction of the
system.
The Stop & Start system makes use
of advanced technology. All work
on this type of battery must be done
by a CITROËN dealer or a qualified
workshop.