Table 4-10. Third-Party Sensor Alert Troubleshooting Guide - Garmin GTN 6 series Maintenance Manual

4.3.1.8 Third-Party Sensors Related Alerts
Alert Text
DATA SOURCE - Pressure
altitude source inoperative or
connection to GTN lost.
GTN 6XX/7XX Part 27 AML STC Maintenance Manual
Page 4-14

Table 4-10. Third-Party Sensor Alert Troubleshooting Guide

Possible Cause
The GTN is configured to receive pressure
altitude, but is not receiving it from any source.
Corrective Action
If the GTN is not expected to receive pressure altitude, ensure that "Altitude
Source Input" is configured for "Not Connected".
Check RS-232 port setting for the port that the device is connected to.
Verify the configuration of the other device.
Verify the GTN RX channel is connected to the remote device TX channel.
Verify there is only one TX source per RX port.
Check wiring.
190-01007-B1
Rev. 1