© 2018 Avco Corporation. All Rights Reserved
Appendix D
November 2018
Page 471
TEO-540-C1A Engine Maintenance Manual
Fault ID
272
Fault Group
35
Fault Name
[FAULT: venturi pressure external]
Fault
Description
Primary: Venturi Pressure 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 A039-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 A039-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
273
Fault Group
35
Fault Name
[FAULT: local deck pressure external]
Fault
Description
Primary: Deck Pressure External
(Sensor Supply Fault)
Secondary: Deck Pressure 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 A045-P
(Primary) or A036 (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 A045-P or A036-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.
