190-02207-A2
GPS 175/GNX 375/GNC 355 Part 23 AML STC Maintenance Manual
Rev. 3
Page 5-9
Figure 5-3 GPS 175/GNC 355 External Transponder Alert Troubleshooting
Transponder is
operating in ground
test mode.
ADS-B Out fault.
Pressure altitude
source inoperative or
connection lost.
ADS-B is not
transmitting position.
Transponder has
failed.
Transponder 1/2
overtemp.
Transponder 1/2
under temp.
GPS 175/GNC 355 External
Transponder Related Alerts
Corrective
Action
Cause
Cause
Cause
Cause
The transponder has
lost communication
with the pressure
altitude source.
Ensure the aircraft has
a clear view of the sky.
The transponder has
detected an internal
fault and transponder
functionality may be
unavailable.
The transponder is
reporting an internal
temperature above its
upper operating limits.
The transponder is
reporting an internal
temperature below its
lower operating limits
.
Corrective
Action
Corrective
Action
Cycle the power to the
transponder.
Verify wiring between
the transponder and
the pressure altitude
source.
If faults still exist,
contact Garmin.
Corrective
Action
Check for adequate
ventilation around the
transponder.
Cause
The transponder has
insufficient data to
support ADS-B.
Corrective
Action
Bring the transponder
within operating
temperatures as
described in the
transponder
installation manual.
Maintenance
Log Message
Transponder has
failed.
<condition>
Corrective
Action
Refer to transponder
installation manual.
Refer to transponder
installation manual.
