JLG 450A_AJ Series II Service Manual - Manual (Page 212)

SECTION 3 - CHASSIS & TURNTABLE
3-162 – JLG Lift – 3121180
3.24 DIAGNOSTIC TROUBLE CODE FAULT
DESCRIPTIONS
DTC 116- ECT Higher Than Expected Stage 1
• Engine Coolant Temperature Sensor.
• Check Condition-Engine Running.
• Fault Condition-Engine Coolant Temperature reading
or estimate greater than stage 1 limit when operating at
a speed greater than defined in 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 1/2 and/or a low rev limit to protect
engine from possible damage.
• Non-emissions related fault.
The Engine Coolant Temperature sensor is a thermistor
(temperature sensitive resistor) located in engine coolant.
Some engines use a CHT sensor located in cylinder head
coolant. Some engines use an ECT (Engine Coolant Tem-
perature) sensor located in coolant near the thermostat. If
engine is equipped with a CHT sensor, the ECT value is
estimated. If equipped with an ECT sensor, the CHT value
is estimated. They are used for engine airflow calculation,
ignition timing control, to enable certain features, and for
engine protection. The ECM provides a voltage divider cir-
cuit. The sensor reads higher voltage when cold and
lower when warm.
This fault helps protect engine in the event of over temper-
ature. When coolant exceeds x deg. F and engine RPM
exceeds y RPM for the latch time this fault will set.
Diagnostic Aids
If “ECT High Voltage” fault is also present, follow trouble-
shooting procedures for that fault as it may have caused
“ECT Higher Than Expected 1.”
Cooling system with air-to-water heat exchanger (radiator)
and fan:
• Check radiator has a proper amount of ethylene glycol/
water and is not leaking.
• Ensure there is no trapped air in cooling path.
• Inspect cooling system (radiator and hoses) for cracks
and connections are leak free.
• Check fan is operating properly.
• Check thermostat is not stuck closed.
Cooling system with water-to-water heat exchanger:
• Check heat exchanger has proper amount of ethylene
glycol/water and that the heat exchanger is not leaking.
• Ensure there is no trapped air in the cooling path.
• Inspect cooling system (radiator and hoses) for cracks
and connections are leak free.
• Check raw water pickup is not blocked/restricted by
debris and hose is tightly connected.
• Check thermostat is not stuck closed.
• Check raw water pump/impeller is intact and not
restricted.
Figure 3-103. Clear Faults Prompt