Lycoming TEO-540-C1A Maintenance Manual page 551

TEO-540-C1A Engine Maintenance Manual
Fault ID 448
Fault
Cowl Flap output failure
Description
This fault occurs to indicate inability to actuate the Cowl flap 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:
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Root Cause
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1. Verify operation of the cowl flap actuator by performing the following steps:
a. Remove connector from cowl flap actuator.
b. Using a power supply (ie. Battery, DC power supply, etc.) and the aircraft wiring diagram manual,
apply power and ground to the appropriate contacts on cowl flap actuator connector for the direction
it needs to move. Does the cowl flap actuator operate? If yes, go to step 2. If no, replace the
actuator. Then go to step 4.
2. Complete a continuity and short circuit test on the cowl flap actuator limit switch. Did tests pass? If no,
replace switch. If yes, go to step 3.
3. Complete a continuity and short circuit test of the harnesses from the cowl flap actuator harness
connector to the ECU connector, including limit switch wiring, using the engine system schematic in
Appendix B and aircraft wiring diagram manual. If the continuity check fails, isolate to affected harness
by disconnecting engine airframe harness and actuator harness. If engine airframe harness is at fault,
contact Lycoming Engines. If aircraft wiring is at fault, repair in accordance with aircraft maintenance
manual. If the continuity checks good, replace ECU.
4. Clear Service faults using the FST by following the steps outlined in the "Access the Field Service
Tool" section in Appendix C or the latest revision of SSP-118.
Fault ID 449
Fault
Description
Root Cause
© 2018 Avco Corporation. All Rights Reserved
November 2018
Fault Group
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
Fault Group
Troubleshooting Steps
57 Fault Name
Fault Lamp
57 Fault Name
Fault Lamp
[FAULT: cowl-flap output failure]
None
-Reserved-
None
Appendix D
Page 521