Appendix D
© 2018 Avco Corporation. All Rights Reserved
Page 518
November 2018
TEO-540-C1A Engine Maintenance Manual
Fault ID
440
Fault Group
56
Fault Name
[FAULT: NTO lamp or Aux fuel
pump output failure]
Fault
Description
Primary: -reserved-
Secondary: NTO Lamp or Aux Pump
Output Failure
Fault Lamp
None
Root Cause
This fault indicates a failure of the NTO lamp output or the Auxiliary pump output on the
secondary channel
Troubleshooting Steps
1.
Is the fault active? If yes, go to step 2. If no, go to step 4.
2.
Is the aux fuel pump (aircraft) controlled by the ECU? If yes, go to step 3. If no, go to NTO
annunciator procedure in this section.
3.
Complete the following steps to determine if the fault is generated by the NTO lamp circuit or the Aux
fuel pump circuit:
a.
Turn ignition on verify the Secondary NTO annunciator flashes. If NTO annunciator flashed, go to
NTO annunciator portion of this procedure. If it did not flash, go the aux fuel pump procedure in
this section.
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.
Aux Fuel Pump Procedure
1.
With power applied to the aircraft, monitor the aux fuel pump pressure indicator, turn the aux pump
switch to ‘ON’. Did the fuel pressure increase? If no, go to step 2. If yes, go to step 3.
2.
Verify power, ground connections, and control switch connections to the fuel pump using the aircraft
wiring diagram manual. Are power and ground present at fuel pump when switch is in the ‘ON’
position? If yes, replace the fuel pump. If no, go to step 7.
3.
Remove the aux fuel pump relay. Complete a continuity test of the harness from the relay connector to
the ECU connector, aux pump switch, and relay power source, using the engine system schematic in
Appendix B and airframe wiring manual. If the continuity check fails between the relay connector and
the ECU, isolate to affected harness by disconnecting the airframe interface connection AF-P1. If the
continuity fails between the relay connector and AF-J1, repair cable in accordance with aircraft
maintenance manual. If the continuity fails between AF-P1 and ECU, contact Lycoming Engines. If the
continuity fails between relay connector and switch, or relay power source, repair cable and/or replace
switch in accordance with aircraft maintenance manual. If the continuity check of the wiring and switch
is good and power is present at relay, replace the relay. Is fault active? If yes, replace the ECU. If no,
go to next step.
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.
NTO Annunciator Procedure
1.
If annunciator uses an incandescent bulb, go to step 2. If annunciator uses an LED bulb, go to step 4.
2.
Replace the bulb. Does fault become inactive. If yes, go to step 3. If no, go to step 4.
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.
4.
Remove connector/wires from annunciator. Complete continuity/short circuit test on annunciator
assembly, using a multi-meter and aircraft wiring manual. If annunciator is defective, replace. If
annunciator passes tests, go to step 5.
5.
Complete a continuity test of the harness from the annunciator to the ECU connector using the engine
system schematic in Appendix B and aircraft wiring diagram manual. If the continuity check fails,
isolate to affected harness by disconnecting AF-P1. 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 annunciator. If fault persists, replace the ECU.
