System Maintenance Manual GTN 6XX/7XX Part 23 AML STC 190-01007-A1Page 5-6 Rev. 55.3 GTN System Messages5.3.1 GTN System Related AlertsTable 5-2. Alert Text Troubleshooting GuideAlert Text Possible Cause Corrective ActionCROSSFILLERROR - Crossfill isinoperative. SeeCRG for crossfilleditems.An error was detected duringunit-to-unit communication ofdata. This can be caused byproblems with HSDB wiring orby either GTN needing service.See the Cockpit ReferenceGuide (CRG) for crossfilleditems.Start both GTNs in Configuration Modeand ensure that both GTNs areconfigured for crossfill.Check J1002 connection on crossfilledGTN units.Ensure that P1002-10 of GTN #2 isconnected to ground.DEMO MODE -Demo mode isactive. Do not usefor navigation.The GTN is in Demo Mode andmust not be used for actualnavigation.Check that the DEMO MODE SELECT*input (P1002-1) is not tied to ground. Alsoensure that the Direct-To key is notstuck.CDI/HSI FLAG -Main lateral/verticalflag on CDI/HSI isinoperative.The main lateral or verticalsuperflag has been turned offdue to an overcurrent condition.Check the GTN main lateral and verticalsuperflag connections to the CDI/HSI forcorrect wiring, shorts to ground, andovercurrent. Superflags should not drivemore than 320 mA.GTN - GTN needsservice.The GTN has detected aninternal failure. Contact Garmin Technical Support.COOLING - GTNovertemp. Reducingbacklightbrightness.The GTN has detectedexcessive display backlighttemperature. The backlight hasbeen automatically dimmed toreduce the unit temperature.Check for adequate ventilation or checkcooling airflow. Also ensure the coolingfan is operating and is unobstructed.KEY STUCK -HOME key is stuck.The bezel’s Home key is stuckin the enabled or pressed state.Press the Home key again to cycle itsoperation. If the message persists,contact Garmin technical support.KEY STUCK -Direct-to key isstuck.The bezel’s Direct-To key isstuck in the enabled or pressedstate.Touch the Direct-To key again to cycle itsoperation. If the message persists,contact Garmin technical support.KNOB STUCK -Dual concentricinner knob is stuckin the pressedposition.The inner large knob push-keyis stuck in the enabled orpressed state. Knob is locatedon the right side of the unit.Press the knob to cycle its operation. Ifthe message persists, contact Garmintechnical support.KNOB STUCK -Volume knob isstuck in the pressedposition.The small knob push-key isstuck in the enabled or pressedstate. Knob is located on the leftside of the unit.Press the knob to cycle its operation. Ifthe message persists, contact Garmintechnical support.
