Lycoming TEO-540-C1A Maintenance Manual page 504

Fault ID 278
Primary: -reserved-
Fault
Secondary: MAP External (Sensor
Description
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-
Root Cause 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.
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 A040-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 A040-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 279
Primary: -reserved-
Fault
Secondary: FPP External (Sensor
Description
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-
Root Cause 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.
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 A014-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 A014-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.
Appendix D
Page 474
Fault Group 35
Supply Fault)
Troubleshooting Steps
Fault Group 35
Supply Fault)
Troubleshooting Steps
TEO-540-C1A Engine Maintenance Manual
Fault Name
[FAULT: manifold pressure external]
Fault Lamp
[FAULT: fuel pump pressure
Fault Name
external]
Fault Lamp
© 2018 Avco Corporation. All Rights Reserved
TLO
TLO
November 2018