Troubleshooting
Teledyne Continental Motors, Inc.
TM
8-6.9. Exhaust Gas Temperature (EGT) Sensor
The ECU monitors independent Exhaust Gas Temperature (EGT) Sensors for each
cylinder. EGT sensing elements are K-type thermocouples. Two conductors made of
dissimilar metals are fused to form the sensing element which produces a small voltage
proportional to the temperature. Voltage changes across the sensing element represent
temperature variations at the sensor tip.
Exhaust Gas Temperature Fault
Disconnect P1 and P2 from the ECUs. Measure
voltage at 50-pin connector pins listed. Sample
temperature to voltage comparisons are in the
table to the right.
Secure the engine low voltage harness.
Perform a FADEC Level I Diagnostic
(Section 8-6-1) or Engine Operational
Check (Sect. 6-1).
Replace ECU
(Sect. 10-11.3 and 10-
11.4).
Use a heat gun to increase temperature at the
EGT sensor tip.
Cut and strip sensor lead wires near
the sensor, allow a 2" pigtail for
splicing. Verify the inner conductor
does not touch the outer shield.
Measure resistance at the faulty
circuit.
NO
CHANGE
VOLTAGE
DECREASES
Replace EGT sensor
(Sect. 10-11.17 and 10-
11.18).
Wiring fault. Use schematic
diagrams and DVM to
locate damaged wires.
Repair wiring (10-10).
Open circuit
Resistance
at or near 0
Remove suspected faulty EGT sensor from the
exhaust system. Allow the sensor to cool to
ambient temperature prior to resistance
measurements
Sensor
Connectors
EGT 1
P1 pins 23 and 39
EGT 2
P1 pins 24 and 40
EGT 3
P2 pins 23 and 39
EGT 4
P2 pins 24 and 40
NOTE: Allow the sensor to cool to
ambient temperature prior to voltage
measurements.
Approximate sensor voltage for sample
ambient temperatures.
Use a DMM, such as a Fluke 179 to
measure voltage.
°F
°C
Voltage (millivolts)
32
0
0.000
77
25
1.000
104
40
1.611
140
60
2.436
176
80
3.266
212
100
4.095
Sensor
Voltage
Change
Circuit
Resistance
Sensor
Connectors
EGT 1
P1 pins 23 and 39
EGT 2
P1 pins 24 and 40
EGT 3
P2 pins 23 and 39
EGT 4
P2 pins 24 and 40
8-20
IOF-240 Series Engine Maintenance Manual
Change 1
31 August 2007