Appendix D
© 2018 Avco Corporation. All Rights Reserved
Page 446
November 2018
TEO-540-C1A Engine Maintenance Manual
Fault ID
188
Fault Group
24
Fault Name
[FAULT: AN19 circuit]
Fault
Description
Primary: -reserved-
Secondary: EOT (Engine Oil Temp.)
Circuit Fault
Fault Lamp
TLO
Root Cause
This fault occurs if the Raw voltage observed on the input is outside the expected window
defined by the calibratable Highest and Lowest Valid Raw voltage values.
This does not distinguish between Open and Short Circuit Faults as any of the following
failures would result in the Raw voltage outside the expected voltage window:
-
Open Circuit
-
Short to VPwr
-
Short to 5V
-
Short to GND
Troubleshooting Steps
1.
Run the engine in accordance with the engine and aircraft maintenance manuals. Is the fault active?
If yes, go to step 3. If no, go to step 2.
2.
Using the FST, download active and service fault logs, then clear fault logs and monitor engine
operation for the fault to repeat.
3.
Inspect the sensor and sensor connector. If either is damaged, replace the sensor per the “Sensor
Replacement Procedure” in Chapter 72-70. If there is no damage, go to step 4.
4.
Inspect engine harness for visible signs of damage. If damage is found, contact Lycoming Engines. If
no damage is found, go to step 5.
5.
Swap the oil temperature sensor with the fuel rail temp sensor (A012) and run the engine. Is there now
an active fuel rail temp circuit fault? If yes, replace the sensor per the “Sensor Replacement Procedure”
in Chapter 72-70. If no, complete a continuity test of the harness from the harness sensor connector 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
189
Fault Group
24
Fault Name
[FAULT: AN20 circuit]
Fault
Description
Primary: Venturi Pressure Circuit Fault
Secondary: Manifold Pressure Circuit
Fault
Fault Lamp
TLO
Root Cause
This fault occurs if the Raw voltage observed on the input is outside the expected window
defined by the calibratable Highest and Lowest Valid Raw voltage values.
This does not distinguish between Open and Short Circuit Faults as any of the following
failures would result in the Raw voltage outside the expected voltage window:
-
Open Circuit
-
Short to VPwr
-
Short to 5V
-
Short to GND
Troubleshooting Steps
1.
Run the engine in accordance with the engine and aircraft maintenance manuals. Is the fault active?
If yes, go to step 3. If no, go to step 2.
2.
Using the FST, download active and service fault logs, then clear fault logs and monitor engine
operation for the fault to repeat.
3.
Inspect the sensor and sensor connector. If either is damaged, replace the sensor per the “Sensor
Replacement Procedure” in Chapter 72-70. If there is no damage, go to step 4.
4.
Inspect engine harness for visible signs of damage. If damage is found, contact Lycoming Engines. If
no damage is found, go to step 5.
5.
Swap the sensor from the channel giving the fault with another sensor in a different position and run the
engine. Did the fault move with the sensor? If yes, replace the sensor per the “Sensor Replacement
Procedure” in Chapter 72-70. If no, complete a continuity test of the harness from the harness sensor
connector 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.
