RAM 1500 2020 Owner's Manual page 115

7. Diesel Exhaust Fluid (DEF) Gauge
The DEF Gauge displays the actual level

of Diesel Exhaust Fluid in the DEF tank.
DEF is required to maintain normal
vehicle operation and emissions compli-
ance. If something is wrong with the
gauge, a DEF Warning Message or
Malfunction Indicator Light (MIL) will be
displayed. Refer to "Diesel Exhaust Fluid
(DEF) Warning Messages" in this chapter
for further information.
WARNING!
A hot engine cooling system is dangerous.
You or others could be badly burned by steam
or boiling coolant. You may want to call an
authorized dealer for service if your vehicle
overheats. If you decide to look under the
hood yourself, refer to "Dealer Service" in
"Servicing And Maintenance". Follow the
warnings under the "Cooling System Pressure
Cap" paragraph.
WARNING!
Driving with a hot engine cooling system
could damage your vehicle. If the tempera-
ture gauge reads "H" pull over and stop the
vehicle. Idle the vehicle with the air condi-
tioner turned off until the pointer drops back
into the normal range. If the pointer remains
on the "H", turn the engine off immediately
and call an authorized dealer for service.
NOTE:
The gauge may take up to five seconds to

update after adding a gallon or more of
Diesel Exhaust Fluid (DEF) to the DEF tank. If
you have a fault related to the DEF system,
the gauge may not update to the new level.
See your authorized dealer for service.
GETTING TO KNOW YOUR INSTRUMENT PANEL
The DEF gauge may also not immediately

update after a refill if the temperature of the
DEF fluid is below 12°F (-11°C). The DEF line
heater will possibly warm up the DEF fluid
and allow the gauge to update after a period
of run time. Under very cold conditions, it is
possible that the gauge may not reflect the
new fill level for several drives.
Outside temperature can affect DEF

consumption. In cold conditions, 12°F
(-11°C) and below, the DEF gauge needle
can stay on a fixed position and may not
move for extended periods of time. This is a
normal function of the system.
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