Navistar ProStar+, Руководство по эксплуатации и обслуживанию, Страница: 180 / 304

Operation
After the key is turned OFF on a vehicle with SCR system, a
pumping sound may be heard from underneath the vehicle. The
sound is made by the Aftertreatment DEF dosing unit while it
purges any unused DEF from the system and returns it to the
DEF tank. This is normal system operation. It takes about 70
seconds to complete.
CAUTION
To prevent vehicle / property damage, after
turning the key OFF on a vehicle with Selective
Catalyst
Reduction (SCR) system, do not
disconnect the vehicle batteries while you
can hear a pumping sound from underneath
the vehicle.
The sound may last for about 60
seconds.
Low DEF Level
WARNING
To prevent property damage, personal injury, and
/ or death, maintain the adequate Diesel Exhaust
Fluid (DEF) level to avoid a loss of engine power
and vehicle speed.
On the instrument panel, you can monitor the fluid level using the
DEF Level Gauge. You will see additional warnings if the DEF
is too low. If DEF level decreases to 2.2% or lower, the engine
performance will start to be derated by at least 25%; if the DEF
level remains 0% for an extended time, the vehicle speed will
be limited to 5 mph (8 km/h). Refill the DEF tank with approved
DEF at any point, and the vehicle will resume normal operation.
See the following table for a detailed explanation of indicators
about low DEF level.
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