RAM 2500 2020 Owner's Manual page 325

2. Insert DEF fill adapter/nozzle into DEF tank
filler neck.
NOTE:
The DEF 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 an autho-
rized dealer for service.
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.
Excessive overfilling of the DEF tank can

result in a MIL lamp/fault code and inac-
curate level readings.
CAUTION!
To avoid DEF spillage, and possible

damage to the DEF tank from overfilling, do
not "top off" the DEF tank after filling.
DO NOT OVERFILL. DEF will freeze below

12ºF (-11ºC). The DEF system is designed
to work in temperatures below the DEF
freezing point, however, if the tank is over-
filled and freezes, the system could be
damaged.
When DEF is spilled, clean the area imme-

diately with water and use an absorbent
material to soak up the spills on the ground.
Do not attempt to start your engine if DEF is

accidentally added to the diesel fuel tank
as it can result in severe damage to your
engine, including but not limited to failure
of the fuel pump and injectors.
STARTING AND OPERATING
CAUTION! (Continued)
Never add anything other than DEF to the

tank – especially any form of hydrocarbon
such as diesel fuel, fuel system additives,
gasoline, or any other petroleum-based
product. Even a very small amount of these,
less than 100 parts per million or less than
1 oz. per 78 Gallons (295 Liters) will
contaminate the entire DEF system and will
require replacement. If owners use a
container, funnel or nozzle when refilling
the tank, it should either be new or one that
is has only been used for adding DEF.
Mopar provides an attachable nozzle with
its DEF for this purpose.
3. Stop filling the DEF tank immediately when
any of the following happen: DEF stops
flowing from the fill bottle into the DEF tank,
DEF splashes out the filler neck, or a DEF
(Continued)
pump nozzle automatically shuts off.
4. Reinstall cap onto DEF tank.
Filling The Def Tank In Cold Climates
Since DEF will begin to freeze at 12°F (-11°C),
your vehicle is equipped with an automatic DEF
heating system. This allows the DEF injection
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