JLG 450A_AJ Series II Service Manual - Manual (Page 157)

SECTION 3 - CHASSIS & TURNTABLE
3121290 – JLG Lift – 3-117
3.18 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 illuminate
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 (tem-
perature sensitive resistor) located in engine coolant. Some
engines use a CHT sensor located in cylinder head coolant.
Some engines use an ECT (Engine Coolant Temperature) sen-
sor 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 circuit. The sensor reads higher volt-
age when cold and lower when warm.
This fault helps protect engine in the event of over tempera-
ture. 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 troubleshoot-
ing 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 gly-
col/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.