Teledyne Continental Motors, Inc.
TM
Troubleshooting
8-6.2. FADEC System Fault Isolation
When troubleshooting the FADEC System, visualize the system as being composed of
the following four major sub-systems:
•
Electronic Control Units (ECUs)
•
The ECUs are the FADEC System controllers; each ECU controls two cylinders.
•
High Voltage Harness
•
The high voltage harness connects the ECU spark coils to the spark plugs.
•
Engine Low Voltage Harness
•
The engine low voltage harness connects the ECUs with the sensor set, pilot
interface devices, and the electrical power sources.
•
Sensor Set
The FADEC sensor set includes all sensors used by the FADEC System to monitor
engine performance. Some sensors are “hard-wired” into the low voltage harness
while others interface with connectors on the low voltage harness. For optimum
FADEC System performance, all sensors must be operational.
Each ECU control channel communicates with unique cylinder head and exhaust gas
temperature sensor. The ECU control channels share the following sensors.
•
Two Intake Manifold Air Temperature Sensors
•
Sensor 1 Odd-numbered control channels
•
Sensor 2 Even-numbered control channels
•
Two Intake Manifold Air Pressure Sensors
•
Sensor Connector P11
Odd-numbered control channels
•
Sensor Connector P12
Even-numbered control channels
•
Two Fuel Pressure Sensors
•
Sensor Connector P9
Channels 1 and 4
•
Sensor Connector P10
Channels 2 and 3
•
Speed Sensor Assembly
•
Sensor Pair 1
Channels 1 and 4
•
Sensor Pair 2
Channels 2 and 3
•
WOT switch on fixed pitch propeller engines
Each control channel performs self-diagnostics. If the ECU detects a sensor fault, an
HSA lamp will be illuminated. TCM FADEC Level I Diagnostic software will
automatically display detected sensor faults on the computer screen. The FADEC Level I
Diagnostic will confirm the existence and nature of detectable system faults. The
software can isolate faults to sensors, a damaged low voltage harness, high voltage
harness, or malfunctioning ECU.
Refer to schematics in Section 8-14 to aid in tracing electrical signals. A FADEC System
malfunction can typically be isolated to one of the four sub-systems listed above.
IOF-240 Series Engine Maintenance Manual
8-13
31 August 2007
Change 1