PEUGEOT 508 Handbook page 184

Driving
Deactivation
At any time, press the "ECO OFF" switch to
deactivate the system.
this is confirmed by the indicator lamp in the
switch coming on accompanied by a message
in the screen.
If the system has been deactivated
in StOP mode, the engine restarts
immediately.
182
Reactivation
Press the "ECO OFF" switch again.
the system is active again; this is confirmed by
the indicator lamp in the switch going off and 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
indicator lamp in the "ECO OFF" switch
flashes then comes on continuously.
Have it checked by a PeugeOt dealer or a
qualified workshop.
In the event of a fault in StOP mode, the
vehicle may stall: all the instrument panel
warning lamps come on. It is then necessary
to switch off the ignition and start the engine
again using the key.