McLaren P1 Owner's Handbook Manual page 64

DRIVING CONTROLS
SEAMLESS SHIFT GEARBOX
The gearbox mode indicator displays M with
the gear number next to it. All forward gear
changes are made by operating the gearshift
paddles, see Gearshift Paddles, page 2.21.
When driving in manual mode, the gear
position indicator will change from orange to
red to indicate that an upshift is required.
NOTE: Manual mode cannot be achieved
in E-Mode.
2.20
Press the MANUAL button again to revert to
Automatic Drive mode. The gearbox mode
indicator will display an A for Automatic and
the gear number next to the letter.
All gear changes occur automatically, but if a
gearshift paddle is operated the gearbox will
adopt a temporary manual mode. This mode
will remain active for as long as the driver
continues to make manual gear changes,
each within an eight second period. The
gearbox mode indicator displays A/M, see
Gear Position Indicator, page 3.30.
NOTE: As soon as an eight second period
has elapsed without a manual gear
change being made, the gearbox will
revert to automatic mode.
The gearbox mode indicator only displays D
when in E-Mode.