Non-Overhaul Removal and Replacement
Teledyne Continental Motors, Inc.
TM
10-44
IOF-240 Series Engine Maintenance Manual
Change 1
31 August 2007
10-10.
Engine Low Voltage Harness Lead Wire Repair and Sensor
Replacement
The engine low voltage harness is made up a several types of lead wires and sensors
which include Exhaust Gas Temperature (EGT) Sensors, the Cylinder Head Temperature
(CHT) Sensors and the Manifold Air Temperature (MAT) Sensors. The non-EGT sensors
are the CHT Sensors and the MAT Sensors. The fuel injector solenoids also are
hardwired to the engine low voltage harness.
CAUTION: Use the proper splice kit for EGT sensors or lead wires.
Using an EGT Splice Kit on a non-EGT sensor or lead wire will
result in abnormal engine operation and may cause engine damage.
NOTE: There are respective Sensor/Wire Splice Kits available
from TCM: one for EGT wires and the other kit is for non-EGT
wires. Be sure to select the proper splice kit and follow the
respective procedure when repairing lead wires and sensors on the
low voltage harness.
Faults detected in the EGT, MAT, and CHT sensors constitute faults in the engine low
voltage harness and require lead wire repair or sensor replacement. If engine low voltage
harness sensors may be replaced and wires may be repaired with the instructions in
Section 10-10.3, “Non-EGT Sensor and Lead Wire Replacement” or sent to the factory or
an authorized service center for repair.
EGT Sensor lead wires are K-type thermocouples and have chromel and alumel
conductors whereas the other low voltage harness conductors are copper and referred to
as “non-EGT” lead wires. Due to physical differences, separate repair procedures are
provided for EGT sensor wire repair or EGT sensor replacement in Section 10-10.2,
“EGT Sensor and Lead Wire Replacement.” The engine low voltage harness may also be
returned to TCM or an authorized service center for repair.
Engine low voltage harness sensors are field replaceable and sensor wiring is repairable,
provided the wires to be repaired are greater than 12 inches (30 cm) from the connectors.
No more than three spliced repairs are permitted in any 12 inch span of the engine low
voltage harness. Pressure sensor wiring repairs may be accomplished using the
instructions in Section 10-10.3, “Non-EGT Sensor and Lead Wire Replacement.”
Special instructions are provided for the Throttle Position Switch in Section 10-11.28.
