Lycoming TEO-540-C1A Maintenance Manual page 496

4. Complete a continuity and short circuit test of the switch. If the continuity or short circuit check fails,
replace the switch. If the continuity check is good, replace the ECU.
5. Complete a continuity test of the harness from the input side of each resistor to the ECU connector using
the engine system schematic. If the continuity check fails, isolate to affected harness by disconnecting
the airframe interface connection AF-P1. If the continuity fails between switch 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 checks good, replace the ECU.
Fault ID 258
Primary: ACJ Temperature Sensor
Fault
Description Secondary: ACJ Temperature Sensor
This fault occurs if the Engineering value of the measured parameter is outside the expected
window defined by the calibratable Highest and Lowest Valid Engineering Values.
Root Cause
The Highest and Lowest possible engineering values define the range of values that can be
expected for the entire engine operating envelope. Any value observed outside this
envelope is flagged as a sensor range fault.
1. With Ignition switch in OFF position, remove ECU power by pulling the ECU circuit breaker. Wait 10s
before resetting. Is fault still active or repetitive? If yes, go to step 2. If no, monitor engine operation
for the fault to repeat. If fault repeats, go to step 2.
2. Check area surrounding ECU and Power Box to ensure there is nothing that could be causing an out of
limit temperature change. If something is found, correct discrepancy. If nothing is found, go to step 3.
3. If fault is still active or repetitive, but is not affecting engine operation, contact Lycoming for further
assistance. If fault affects engine operation (ie... causes other faults), replace the ECU.
Fault ID 259
Primary: Thermocouple Offset Sensor
Fault
Description Secondary: Thermocouple Offset
This fault occurs if the Engineering value of the measured parameter is outside the expected
window defined by the calibratable Highest and Lowest Valid Engineering Values.
Root Cause The Highest and Lowest possible engineering values define the range of values that can be
expected for the entire engine operating envelope. Any value observed outside this
envelope is flagged as a sensor range fault.
1. With Ignition switch in OFF position, remove ECU power by pulling the ECU circuit breaker. Wait 10s
before resetting. Is fault active? If no, go to step 3. If yes, are there any other active EGT or CHT
faults? If yes, go to corresponding troubleshooting procedure for the active fault.
2. 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.
3. If fault repeats, replace the ECU.
Appendix D
Page 466
Troubleshooting Steps (Cont.)
Fault Group
Range Fault
Range Fault
Troubleshooting Steps
Fault Group
Range Fault
Sensor Range Fault
Troubleshooting Steps
TEO-540-C1A Engine Maintenance Manual
33 Fault Name
Fault Lamp
33 Fault Name
Fault Lamp
© 2018 Avco Corporation. All Rights Reserved
[FAULT: ACJ temperature range]
TLO
[FAULT: thermocouple offset
voltage range]
TLO
November 2018