JLG 460SJ Service Manual - Manual (Page 216)

SECTION 3 - CHASSIS & TURNTABLE
3-164 – JLG Lift – 3120895
DTC 217- ECT Higher Than Expected 2
• Engine Coolant Temperature Sensor
• Check Condition-Engine Running
• Fault Condition-Engine Coolant Temperature reading
or estimate greater than the stage 2 limit when operat-
ing at a speed greater than defined in the diagnostic
calibration
• Corrective Action(s)- Sound audible warning or illumi-
nate secondary warning lamp, disable adaptive learn
fueling correction during active fault. Recommend a
power derate 2 and/or a forced idle or engine shut-
down to protect engine from possible damage.
• Non-emissions related fault
The Engine Coolant Temperature sensor is a thermistor
(temperature sensitive resistor) located in the engine cool-
ant. Some engines use a CHT sensor that is located in the
coolant in the cylinder head. Some engines use an ECT
(Engine Coolant Temperature) sensor that is located in the
coolant near the thermostat. If the engine is equipped with
a CHT sensor then the ECT value is estimated. If equipped
with an ECT sensor then the CHT value is estimated. The
ECM provides a voltage divider circuit so when the sensor
reading is cool the sensor reads higher voltage, and lower
when warm.
This fault will help protect the engine in the event of over
temperature. When the coolant exceeds x deg. F and
engine RPM exceeds y RPM for the latch time this fault will
set.
Diagnostic Aids
If the "ECT High Voltage" fault is also present, follow the
troubleshooting procedures for that fault as it may have
caused "ECT Higher Than Expected 2."
If the cooling system utilizes an air-to-water heat
exchanger (radiator) and fan:
• Check that the radiator has a proper amount of ethyl-
ene glycol/water and that the radiator is not leaking
• Ensure that there is no trapped air in the cooling path
• Inspect the cooling system (radiator and hoses) for
cracks and ensure connections are leak free
• Check that the fan is operating properly
• Check that the thermostat is not stuck closed
If the cooling system utilizes a water-to-water heat
exchanger:
• Check that the heat exchanger has a proper amount of
ethylene glycol/water and that the heat exchanger is
not leaking
• Ensure that there is no trapped air in the cooling path
• Inspect the cooling system (radiator and hoses) for
cracks and ensure connections are leak free
• Check that the raw water pickup is not blocked/
restricted by debris and that the hose is tightly con-
nected
• Check that the thermostat is not stuck closed
• Check that the raw water pump/impeller is tact and that
it is not restricted