Maintenance Manual
190-02472-02
G3X Touch EFIS Part 23 AML STC
Revision 2
Page 44
If the magnetic interference test fails, the installation should be considered unreliable until the source of
magnetic interference is identified and remedied. The magnetometer interference test must be repeated
until passed. When the magnetometer interference test fails, record the magnetometer maximum deviation
values, and the corresponding timestamps. A maximum deviation value greater than 100% of the total limit
in any axis indicates a problem that must be resolved. Compare the corresponding timestamps with the
prepared test sequence to identify which action produced the problem. Contact Garmin for assistance in
resolving the problem.
NOTE
Two common reasons for a failed magnetometer interference test are:
new equipment is installed in close proximity to the GMU magnetometer or
An existing or new electronic device has become grounded through the aircraft structure instead
of by proper ground wire in a twisted shielded pair, or
Use of magnetized tools in close proximity to the GMU 11.
5.5 Engine Indication Troubleshooting
EIS indication failures may be presented as red x’s on the gauges as shown in Figure 5-9, or as operation
anomalies. Reference Table 5-8 below for troubleshooting guidance.
Figure 5-9 – Engine/Airframe Failure Indications
Table 5-8 – EIS Gauges Troubleshooting
Symptom or Failure
Message
Possible Cause
Recommended Action
Power removed from GEA
24
Defective or failed GEA 24
Ensure GEA 24circuit breaker is not open.
Inspect wiring and electrical connections.
If problem persists, replace the GEA 24 with a
known good unit.
Engine Indications Red
X’d
Power interrupted during
initialization
Cycle power and permit time for initialization
Software and configuration
load error
Reload software
EGT/CHT only Red X’d
Temperature probe is
shorted
(typically where the
bayonet is crimped)
Inspect temperature probe(s) and wiring
EGT temperature slowly
drift up and eventually
flag
Electrical open in the probe
or wiring
Inspect EGT probes and wiring
Unstable RPM
Resistor failure
Disconnect P-Lead signal wires at
both ends. Verify wire is more than 400 K
Ω
.
Replace wire and parallel resistors if less than
400 K
Ω
Poor connection
Verify wiring and connections
Interference
Route signal wires away from spark plug
leads and power wires
Summary of Contents for G3X Touch
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