Avidyne IFD540 Pilot's Manual page 184

Short Text
Low Volts
Manual Sequence
Req'd
6-8 General
Text
Long
Backlight reduced to 25%
Altitude invalid – leg will not auto
sequence
Comments
Main supply voltage has
fallen to approximately
11VDC.
Check the aircraft
alternators are on and
functional.
Consider load shedding
the power bus that is
powering the IFD.
In basic E-M aircraft
where the IFD does not
have altitude input, this
message will appear when
the FMS active leg is a
HeadingAltitude leg. In
this case, the FMS flight
plan will need to be
manually sequenced to
the next leg. Failure to do
so will keep the FMS
flying the heading
indefinitely.