Appendix D
© 2018 Avco Corporation. All Rights Reserved
Page 472
November 2018
TEO-540-C1A Engine Maintenance Manual
Fault ID
274
Fault Group
35
Fault Name
[FAULT: local compressor inlet air
pressure external]
Fault
Description
Primary: CIP External (Sensor Supply
Fault)
Secondary: CIP External (Sensor
Supply Fault)
Fault Lamp
TLO
Root Cause
This fault implies that the 5V sensor supply that is connected to the sensor is deemed
INVALID.
1: The 5V supply may be INVALID due to a circuit fault or a slew-rate fault on the 5V supply.
For details of the 5V Supply faults refer to Fault Ids 160-162, 196-198 and 264-266.
2: Multiple sensors may be connected to the same 5V supply so if it becomes INVALID then
all the sensors that are connected to it would set corresponding External (sensor supply)
faults. Refer to the system schematic to identify the sensors that may be connected to a 5V
supply.
Troubleshooting Steps
1.
Is there an active fault(s) that correspond to the fault numbers listed in the Root Cause box, items 1 and
2? If yes, go to troubleshooting procedure for the active fault(s). If no, go to step 2.
2.
With the ECU powered on, use a multi-meter to measure the voltage at the sensor connector A037-P
(Primary) or A038 (Secondary) pin C (5V supply) and pin A (GND). Is 5V present on pin C? If yes,
replace the sensor. If no, go to step 3.
3.
Inspect engine harness for visible signs of damage. If damage is found, contact Lycoming Engines. If
no damage is found, go to step 4.
4.
Complete a continuity test of the harness from the harness sensor connector A037-P or A038-P 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.
Fault ID
275
Fault Group
35
Fault Name
[FAULT: engine oil pressure external]
Fault
Description
Primary: EOP External (Sensor Supply
Fault)
Secondary -reserved-
Fault Lamp
TLO
Root Cause
This fault implies that the 5V sensor supply that is connected to the sensor is deemed
INVALID.
1: The 5V supply may be INVALID due to a circuit fault or a slew-rate fault on the 5V supply.
For details of the 5V Supply faults refer to Fault Ids 160-162, 196-198 and 264-266.
2: Multiple sensors may be connected to the same 5V supply so if it becomes INVALID then
all the sensors that are connected to it would set corresponding External (sensor supply)
faults. Refer to the system schematic to identify the sensors that may be connected to a 5V
supply.
Troubleshooting Steps
1.
Is there an active fault(s) that correspond to the fault numbers listed in the Root Cause box, items 1 and
2? If yes, go to troubleshooting procedure for the active fault(s). If no, go to step 2.
2.
With the ECU powered on, use a multi-meter to measure the voltage at the sensor connector A025-P pin
B (5V supply) and pin A (GND). Is 5V present on pin B? If yes, replace the sensor. If no, go to step 3.
3.
Inspect engine harness for visible signs of damage. If damage is found, contact Lycoming Engines. If
no damage is found, go to step 4.
4.
Complete a continuity test of the harness from the harness sensor connector A025-P 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.
