© 2018 Avco Corporation. All Rights Reserved
Appendix D
November 2018
Page 511
TEO-540-C1A Engine Maintenance Manual
Fault ID
416
Fault Group
53
Fault Name
[FAULT: crank vs cam speed
discrepancy]
Fault
Description
Crank Vs Cam speed discrepancy fault
Fault Lamp
TLO
Root Cause
This fault indicates the engine speed calculated from the Crank differs from the engine
speed calculated from the Cam by more than a maximum calibrated threshold. This fault
will become inactive if the Crank and Cam speeds converge.
Troubleshooting Steps
1.
Is there a corresponding cam or crankshaft sensor circuit fault, active or logged? If yes, replace the
sensor with corresponding fault. If no, go to step 2.
2.
Run the engine in accordance with the engine and aircraft maintenance manuals. Is the fault active? If
yes, go to step 4. If no, go to step 3.
3.
Using the FST, download active and service fault logs. Review logs to ensure the engine was not
operated in a placarded region identified by Lycoming Engines. Then go to step 8.
4.
Inspect the cam and crank sensors, sensor leads and connectors. If there is damage found, replace the
damaged sensor per the “Sensor Replacement Procedure” in Chapter 72-70. If there is no damage, go to
step 5.
5.
Inspect engine harness for visible signs of damage. If damage is found, contact Lycoming Engines. If
no damage is found, go to step 6.
6.
Swap the crank sensor with a new sensor and run the engine. Is the fault active? If yes, swap the new
sensor in the crank position with the cam sensor, reinstall the original crank sensor, and run the engine.
Is the fault active? If yes, go to step 7. If no, go to step 8.
7.
Complete a continuity test of the harness from the engine harness crank and cam sensor connectors to
the ECU connector 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
checks good, replace the ECU.
8.
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
417
Fault Group
53
Fault Name
[FAULT: engine over speed]
Fault
Description
Engine over speed fault
Fault Lamp
TLO
Root Cause
This fault indicates the engine speed has exceeded its speed limit for more than the
calibrated time to initiate cylinder cut.
Troubleshooting Steps
1.
Using the FST, download active and service fault logs. Review logs to verify the occurrence of an
engine overspeed (2750 RPM exceeding 3 seconds) as defined in the latest revision of SB369, Engine
Inspection after Overspeed. If overspeed occurred, go to step 2. If the overspeed did not occur or is
within the limits of a momentary overspeed as defined by SB369, go to step 3.
2.
Complete overspeed inspection in accordance with the latest revision of SB369.
3.
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.
