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Appendix D
© 2018 Avco Corporation. All Rights Reserved
Page 420
November 2018
TEO-540-C1A Engine Maintenance Manual
Fault ID
91
Fault Group
12
Fault Name
[FAULT: prop-pitch output failure]
Fault
Description
Prop-pitch output driver fault
Fault Lamp
NTO
Root Cause
This fault occurs to indicate inability to control the Propeller Pitch actuator as desired due
to a circuit fault. The circuit fault may be internal to the ECU (drive stage) or external to
the ECU (load or harness).
The fault is set under any one of the following conditions:
-
The actuator or the drive stage is Open-circuit
-
The actuator is short-circuited
-
Low Side Drive (LSD) is shorted to the GND
-
High Side Drive (HSD) is shorted to the GND
-
LSD is shorted to the V Supply
-
HSD is shorted to the V Supply
Troubleshooting Steps
1.
Run the engine in accordance with the engine and aircraft maintenance manuals. Is the fault active? If
yes, go to step 2. If no, go to step 3.
2.
Are there faults on both primary and secondary channels for the propeller governor? If yes, go to step 5.
If no, go to step 6.
3.
Using the FST, download active and service fault logs. Go to step 4.
4.
Review logs to determine which fault was set, and if there are more than one fault. If there are no active
faults, but fault(s) keep reoccurring, go to step 5.
5.
If faults are found on both channels, inspect harness for damage (eg…burned, broken or frayed wires,
cracked or broken connectors). If damage found, contact Lycoming. If no damage found, replace the
propeller governor.
6.
Inspect propeller governor harness connection for any damage (eg…burned, broken or frayed wires,
cracked or broken connectors). Contact Lycoming if harness damage is found. If no damage is found,
go to step 7.
7.
Complete a continuity test of the harness from the harness injector connector to ECU connector A001-
P3, and A001-P4, using the engine system schematic. If the continuity check fails, isolate to affected
harness by disconnecting the firewall connection, then contact Lycoming Engines. If the continuity
check is good, replace the ECU.
Fault ID
92
Fault Group
12
Fault Name
-reserved-
Fault
Description
Fault Lamp
NTO
Root Cause
Troubleshooting Steps
Fault ID
93
Fault Group
12
Fault Name
-reserved-
Fault
Description
Fault Lamp
NTO
Root Cause
Troubleshooting Steps