JLG 510AJ Service Manual - Manual (Page 142)

SECTION 3 - CHASSIS AND TURNTABLE
3-100 – JLG Lift – 3121181
3.15 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 the stage 1 limit when operating at a
speed greater than defined in the 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 the engine coolant.
Some engines use a CHT sensor that is located in the coolant
in the cylinder head. Some engines use an ECT (Engine Cool-
ant 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. They are used for engine air-
flow calculation, ignition timing control, to enable certain fea-
tures, and for engine protection. 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 tem-
perature. 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 trou-
bleshooting procedures for that fault as it may have caused
"ECT Higher Than Expected 1."
If the cooling system utilizes an air-to-water heat exchanger
(radiator) and fan:
• Check radiator has a proper amount of ethylene glycol/
water and is not leaking
• Ensure that there is no trapped air in the cooling path
• Inspect cooling system (radiator and hoses) for cracks and
ensure connections are leak free
• Check fan is operating properly
• Check thermostat is not stuck closed
If cooling system utilizes a water-to-water heat exchanger:
• Check heat exchanger has a proper amount of ethylene
glycol/water and is not leaking
• Ensure there is no trapped air in the cooling path
• Inspect cooling system (radiator and hoses) for cracks and
ensure 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