Komatsu D61EX-24 Operation & Maintenance Manual page 188

OPERATION EXPLANATION OF COMPONENTS
About the operation in cold weather
DEF freezes at –11 °C {12.2 °F} .
Urea SCR system is equipped with a heating system to thaw frozen DEF once it is frozen, for example, during
parking and to prevent DEF from freezing during operation.
In case DEF freezes during parking, once the engine starts running the heating system automatically starts pro-
viding heat to thaw frozen DEF. The pump and the injector start working only after a proper amount of DEF is
thawed. This may be noticed as a delay in the start of functioning of the pump and the injector.
The heating system is also activated automatically during operation to prevent DEF from freezing whenever the
ambient temperature drops below a certain threshold where DEF in the system may freeze. In the event that the
ambient temperature drops further than a temperature where the heating system is capable of maintaining fluidi-
ty of DEF, the DEF system automatically starts purging the remaining DEF back to the tank and stops pumping
and injection while heating continues. Once the ambient temperature rises above a temperature where DEF
system becomes functional, it resumes operation automatically.
Short duration of white plume given off from the tail pipe may be visible at and shortly after engine start-up in
cold weather, but this is not malfunction.
Inducement strategy when the DEF tank Level becomes low
When the amount of DEF in the tank goes low, the Inducement strategy will be activated.
If Inducement starts, add DEF to the DEF tank immediately.
The DEF level caution lamp (1) on the monitor lights up, the audible alert starts, and the Action level is dis-
played, and Inducement strategy is activated. Inducement strategy includes engine output deration, speed limi-
tation, or other warning actions intend to prompt the operator to maintain or repair SCR system.
The Inducement strategy progressed in 5 levels from Warning, Escalated Warning, Mild inducement, Severe In-
ducement and Final Inducement.
The DEF level caution lamp (1) on the machine monitor will
light up, audible alert will start, then Action level will be dis-
played on the machine monitor, and engine power will be derat-
ed in steps.
In Action Level "L03 (Mild Inducement)" and "L04 (Severe In-
ducement and Final Inducement)" engine power will be derat-
ed. When Action Level "L03" or "L04" is displayed, move the
machine to a safe place and add DEF.
If operation is continued further without adding DEF at Severe
Inducement, engine speed will be fixed at low idle. (Final In-
ducement)
The content of the warning can be checked on the "SCR Information" screen of the user menu.
Perform the following procedure.
Press F6 on the standard screen to display the "SCR Informa-
tion" screen of the user menu.
If either the parking brake lever and work equipment lock lever
are set to LOCK position or the joystick (steering, directional
and gear shift lever) is in NEUTRAL position for over 3 sec-
onds, "SCR Information" screen of the user menu will pop up
automatically while the Urea SCR system is in Inducement.
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