RAM 2500 2023 Owner's Manual page 115

Cold Ambient Derate Mode Messages
The vehicle will display messages when a derate (engine
power reduction) is activated to protect the engine during
start-up in cold ambient temperatures.
 Engine Power Reduced During Warm-up — This
message will display during start-up when the
ambient temperature is between 10°F (-12°C) and
-10°F (-23°C).
 Engine Power Reduced Up To 30 Sec (Seconds) During
Warm-up — This message will display during start-up
when the ambient temperature is between -10°F
(-23°C) and -25°F (-32°C).
 Engine Power Reduced Up To 2 Min (Minutes) During
Warm-up — This message will display during start-up
when the ambient temperature is -25°F (-32°C) and
below.
Your vehicle is equipped with an engine warm up
protection feature that may limit engine performance
after cold starting at low ambient temperatures. The
length of time engine speed is limited is dependent
upon engine coolant temperature. Engine speed may
be briefly limited to 1,000 RPM after starting with
coolant temperature below freezing conditions, and
may be limited to 1,000 RPM for up to approximately
two minutes under more severe cold conditions.
 Coolant Low — This telltale will turn on to indicate the
vehicle coolant level is low page 381.
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Diesel Exhaust Fluid (DEF) Warning
Messages
There are four different messages which are displayed if
the vehicle detects that the DEF system has been filled
with a fluid other than DEF, has experienced component
failures, or when tampering has been detected. The
vehicle may be limited to a maximum speed of 5 mph
(8 km/h) if the DEF system is not serviced within less than
200 miles (322 km) of the fault being detected.
When the DEF system needs to be serviced the following
warnings will display:
 DEF Low Refill Soon — This message will display when
the low level is reached, during vehicle start-up, and
with increased frequency during vehicle operation. It
will be accompanied by a single chime. Approximately
5 gallons (19 Liters) of DEF is required to refill the tank
when this message is initially displayed. on pickup
applications, and approximately 7 gallons (26 Liters)
are required on chassis-cab applications.
 Speed Limited to 5 MPH in XXX mi Refill DEF — This
message will continuously display if the "DEF Low Refill
Soon" message is ignored, and the frequency of occur-
rence of the chime will increase unless up to 2 gallons
(7.5 Liters) of DEF is added to the tank.
GETTING TO KNOW YOUR INSTRUMENT PANEL
 5 MPH Max Speed on Restart, Long Idle or Refuel Refill
DEF — This message will continuously display when the
counter reaches zero, and will be accompanied by a
periodic chime.
The vehicle will only be capable of a maximum speed of
5 mph upon the first of the following conditions to
occur:
 If the vehicle is shut off and restarted.
 If the vehicle is idled for an extended period of
time, approximately one hour or greater.
 If the system detects that the level of fuel in the
tank has increased.
Add a minimum of 2 gallons (7.5 Liters) of DEF to the
tank in order to avoid vehicle operation at a maximum
speed of 5 mph (8 km/h).
NOTE:
A minimum of 2 gallons (7.5 Liters) may be required to
restore normal vehicle operation. Although the vehicle will
start normally and can be placed in gear after this
message has been initially displayed, extreme caution
should be utilized since the vehicle will only be capable of
maneuvering at a maximum speed of 5 mph (8 km/h).
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