CITROËN DS4 Owner's Handbook Manual page 208

Stopping the vehicle
Before switching off the engine, you can
choose to:
- move to position N to engage neutral,
- leave the gear engaged; in this case,
it will not be possible to move the vehicle.
In both cases, you must apply the parking
brake to immobilise the vehicle.
When immobilising the vehicle, with
the engine running, you must place the
gear lever in neutral N .
Before carrying out any work in the
engine compartment, check that the
gear lever is in neutral N and that the
parking brake is applied.
Operating fault
With the ignition on, the flashing of AUTO ,
accompanied by an audible signal and a
message in the multifunction screen, indicates
a malfunction of the gearbox.
Have it checked by a CITROËN dealer or a
qualified workshop.
You must press the brake pedal when
starting the engine.
Whatever the circumstances, you must
manually apply the parking brake when
parking, unless the parking brake is
programmed in automatic mode.