Garmin Diamond DA40, Maintenance Manual

Page: 83 / 156

G1000/DA40 System Maintenance Manual Page 5-21
190-00303-03 Revision 6
5.11 GRS 77/GMU 44 Troubleshooting
5.11.1 GRS Alerts
Failure Message Cause Solutions
MANIFEST – GRS1 software
mismatch. Communication
Halted. The system has detected an
incorrect software version loaded
in GRS 77.
•
Reload software. See Section 7 for
GRS 77 Software Load Procedure.
AHRS SERVICE – AHRS
Magnetic-field model needs
update. The AHRS magnetic field model
should be updated. Appears on
ground only.
See Section 4.7.
GEO LIMITS – Too far
North/South, no magnetic
compass.
The aircraft is outside of its
operating limits; i.e., too far North
or South. Heading will be flagged
invalid.
Operate the aircraft only within the limits
as specified in the
G1000/DA 40 AFMS.
AHRS TAS – AHRS not receiving
airspeed. The GRS 77 is not receiving
airspeed from the GDC 74A.
Check GRS/GDC interconnect.
AHRS GPS – AHRS not receiving
GPS information. The GRS 77 is not receiving GPS
data from the GPS receivers.
AHRS GPS – AHRS using backup
GPS source. The GRS 77 is using the backup
GPS data path.
Ensure that both GPS1 and GPS2 can
lock on to GPS signals:
9 If GPS receivers are faulty,
replace GIA unit(s).
If GPS receivers operate correctly, check
GRS/GIA interconnects:
9 If interconnects operate
correctly, replace GRS 77.
5.11.2 GMU Alerts
Failure Message Cause Solutions
MANIFEST – GMU1 software
mismatch. Communication
Halted. The system has detected an
incorrect software version loaded
in GMU 44.
Reload software. See Section 7 for
GMU 44 Software Load Procedure.
HDG FAULT – A magnetometer
fault has occurred.
A fault has occurred in the
magnetometer; heading will be
flagged invalid.
Replace GMU 44.