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Page 4-4
GNS 400W Series Maintenance Manual
Rev. A
190-00356-05
Table 4-1. Fault Messages and Recommended Actions (continued)
Data card write failure/Data
card failure
N/A
Replace the Jeppesen
NAVData® card.
Check the applicable flex
cable.
Return the unit for service.
Display backlight failure
N/A
Return the unit for service.
G/S has failed
N/A
Replace the glideslope board.
Return the unit for service.
G/S is not responding
Internal system-to-system
communication between the
main processor and the
glideslope receiver has failed.
Operational status of the
glideslope receiver is
unknown.
Check the applicable flex
cable.
Replace the glideslope board.
G/S needs service
N/A
Replace the glideslope board.
GPS has failed
N/A
Replace the WAAS GPS
module.
GPS needs service
The unit has detected a
failure in its GPS receiver.
The GPS receiver may still be
usable.
Press the switch again to
cycle its operation.
Return the unit for service.
Replace the GPS module.
GPS stored data was lost
N/A
Return the unit for service.
Heading input failure
N/A
Return the unit for service.
Low Battery Unit Needs
Service
Time data may have been
lost due to a memory battery
failure.
Replace the memory battery.
Return the unit for service.
Main processor requires
service
The unit has detected a
failure in the main system
processor.
Return the unit for service.
No basemap data available
The unit has detected a
failure in the built-in basemap
(land data) memory. Land
data does not appear on the
map page. Other unit
functions continue to work
normally.
Insert the terrain data card in
right data card slot (for
TAWS/TERRAIN units).
Replace the terrain data card.
Replace the map board.
Return the unit for service.
