2020 Ram 2500 coolant temperature

126GETTING TO KNOW YOUR INSTRUMENT PANEL
Exhaust Filter Full — Power Reduced See
Dealer — This message indicates the PCM
has derated the engine to limit the likelihood
of permanent damage to the after-treatment
system. If this condition is not corrected and
a dealer service is not performed, extensive
exhaust after-treatment damage can occur.
To correct this condition it will be necessary
to have your vehicle serviced by your local
authorized dealer.
NOTE:
Failing to follow the oil change indicator,
changing your oil and resetting the oil change
indicator by 0 miles remaining will prevent the
diesel exhaust filter from performing it's
cleaning routine. This will shortly result in a
Malfunction Indicator Light (MIL) and reduced
engine power. Only an authorized dealer will be
able to correct this condition.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 Warmup —
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 Warmup — 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 Warmup — 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 1000 RPM after
starting with coolant temperature below freezing conditions, and may be limited to
1000 RPM for up to approximately 2 minutes
under more severe cold conditions.
Coolant Low
— This telltale will turn on to indi -
cate the vehicle coolant level is low. Refer to
“Dealer Service” in “Servicing And Mainte -
nance” for more information.
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. Approxi -
mately 5 gallons (19 Liters) of DEF is required
to refill the tank when this message is initially CAUTION!
See an authorized dealer, as damage to the
exhaust system could occur soon with
continued operation.

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GETTING TO KNOW YOUR INSTRUMENT PANEL131
the brake fluid level in the master cylinder has
dropped below a specified level.
The light will remain on until the cause is
corrected.
NOTE:
The light may flash momentarily during sharp
cornering maneuvers, which change fluid level
conditions. The vehicle should have service
performed, and the brake fluid level checked.
If brake failure is indicated, immediate repair is
necessary.
Vehicles equipped with the Anti-Lock Brake
System (ABS) are also equipped with Electronic
Brake Force Distribution (EBD). In the event of
an EBD failure, the Brake Warning Light will turn
on along with the ABS Light. Immediate repair to
the ABS system is required. Operation of the Brake Warning Light can be
checked by turning the ignition switch from the
OFF position to the ON/RUN position. The light
should illuminate for approximately two
seconds. The light should then turn off unless
the parking brake is applied or a brake fault is
detected. If the light does not illuminate, have
the light inspected by an authorized dealer.
The light also will turn on when the parking
brake is applied with the ignition switch in the
ON/RUN position.
NOTE:
This light shows only that the parking brake is
applied. It does not show the degree of brake
application.
Hood Open Warning Light
This warning light will illuminate when
the hood is ajar/open and not fully
closed.
NOTE:
If the vehicle is moving, there will also be a
single chime.
Vehicle Security Warning Light — If Equipped
This light will flash at a fast rate for
approximately 15 seconds when the
vehicle security alarm is arming, and
then will flash slowly until the vehicle
is disarmed.
Engine Coolant Temperature Warning Light
This warning light warns of an over -
heated engine condition. If the engine
coolant temperature is too high, this
indicator will illuminate and a single
chime will sound. If the temperature reaches
the upper limit, a continuous chime will sound
for four minutes or until the engine is able to
cool; whichever comes first.
If the light turns on while driving, safely pull over
and stop the vehicle. If the Air Conditioning
(A/C) system is on, turn it off. Also, shift the
transmission into NEUTRAL and idle the vehicle.
If the temperature reading does not return to
normal, turn the engine off immediately and call
for service.
Refer to “If Your Engine Overheats” in “In Case
Of Emergency” for further information.
WARNING!
Driving a vehicle with the red brake light on is
dangerous. Part of the brake system may
have failed. It will take longer to stop the
vehicle. You could have a collision. Have the
vehicle checked immediately.
3

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218STARTING AND OPERATING
5. After engine start-up, check to see that
there is oil pressure.
6. Release the parking brake and drive.
NOTE:
Engine idle speed will automatically increase
to 1,000 RPM and engage the Variable
Geometry Turbocharger at low coolant
temperatures to improve engine warm-up.
The engine will not automatically crank after
the engine “Wait To Start” telltale goes off if
a door or the hood is ajar.
If the engine stalls, or if the ignition switch is
left ON for more than two minutes after the
“Wait To Start” telltale goes out, reset the
intake air heater by turning the ignition
switch to the OFF position for at least
5 seconds and then back ON. Repeat steps
1 through 7 of “Keyless Enter-N-Go Starting Procedure – Engine Manifold Air Tempera
-
ture Below 66° F (19° C).”
Extreme Cold Weather
The Cummins® Turbo Diesel engine is
equipped with several features designed to
assist cold weather starting and operation:
The engine block heater is a resistance
heater installed in the water jacket of the
engine just above and behind the oil filter. It
requires a 110–115 Volt AC electrical outlet
with a grounded, three-wire extension cord.
NOTE:
The engine block heater cord is a factory
installed option. If your vehicle is not equipped,
heater cords are available from an authorized
Mopar dealer.
A 12 Volt heater built into the fuel filter hous -
ings aid in preventing fuel gelling. It is
controlled by a built-in thermostat.
A intake air heater system both improves
engine starting and reduces the amount of
white smoke generated by a warming engine.
Normal Starting Procedure — Engine
Manifold Air Temperature Above 66° F
(19° C)
Observe the instrument panel cluster lights
when starting the engine.

1. Always apply the parking brake.

2. Shift into PARK for an automatic transmis -
sion.
3. Place the ignition switch in the ON position and watch the instrument panel cluster
lights.
4. Place the ignition switch in the START posi -
tion and crank the engine. Do not press the
accelerator during starting.
CAUTION!
Do not crank engine for more than 25 seconds
at a time or starter motor damage may result.
Turn the ignition switch to the OFF position and
wait at least two minutes for the starter to cool
before repeating start procedure.
CAUTION!
If the “Water in Fuel Indicator Light” remains
on, DO NOT START the engine before you
drain the water from the fuel filters to avoid
engine damage. Refer to “Draining Fuel/
Water Separator Filter” in “Servicing And
Maintenance” for further information.

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STARTING AND OPERATING219
5. Check that the oil pressure warning light
has turned off.
6. Release the parking brake.
Starting Procedure — Engine Manifold Air
Temperature 0°F To 66°F (–18°C to 19°C)
NOTE:
The temperature displayed in the instrument
cluster does not necessarily reflect the engine
manifold air temperature. Refer to “Instrument
Cluster Display” in “Getting To Know Your
Instrument Panel” for further information.
When engine temperatures fall below 66°F
(19°C) the “Wait To Start Light” will remain on
indicating the intake air heater system is active.
Follow the steps in the “Normal Starting” proce -
dure except:
1. The “Wait To Start” telltale will remain on
for a period of time that varies depending
on the engine temperature.

2. While the “Wait To Start” telltale is on, the instrument cluster will additionally display a
gauge or bar whose initial length represents
the full “Wait To Start” time period. Its
length will decrease until it disappears
when the “Wait To Start” time has elapsed.
3. After the “Wait To Start” telltale goes off, place the ignition switch in the START posi -
tion. Do not press the accelerator during
starting. 4. After engine start-up, check that the oil
pressure warning light has turned off.
5. Release the parking brake and drive.
NOTE:
Engine idle speed will automatically increase
to 1,000 RPM and engage the Variable
Geometry Turbocharger at low coolant
temperatures to improve engine warm-up.
Automatic equipped vehicles with optional
Keyless Enter-N-Go – If the start button is
pushed once while in park with the ignition
off and driver’s foot on the brake pedal, the
vehicle will automatically crank and start
after the Wait to Start time has elapsed. If it
is desired to abort the start process before it
CAUTION!
Do not crank engine for more than 25 seconds
at a time or starter motor damage may result.
Turn the ignition switch to the OFF position and
wait at least two minutes for the starter to cool
before repeating start procedure.
CAUTION!
If the “Water in Fuel Indicator Light” remains
on, DO NOT START the engine before you
drain the water from the fuel filters to avoid
engine damage. Refer to “Draining Fuel/
Water Separator Filter” in “Servicing And
Maintenance” for further information.
CAUTION!
Do not crank engine for more than 25 seconds
at a time or starter motor damage may result.
Turn the ignition switch to the OFF position and
wait at least two minutes for the starter to cool
before repeating start procedure.
5

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220STARTING AND OPERATING
completes, the driver’s foot should be fully
removed from the brake pedal prior to
pushing the start button again in order for the
ignition to move directly to off.
If the engine stalls, or if the ignition switch is
left ON for more than two minutes after the
“Wait To Start” telltale goes out, reset the
intake air heater by turning the ignition
switch to the OFF position for at least five
seconds and then back ON. Repeat steps
1 through 5 of “Starting Procedure – Engine
Manifold Air Temperature Below 66°F
(19°C).”
Starting Procedure — Engine Manifold Air
Temperature Below 0°F (-18°C)
In extremely cold weather below 0°F (-18°C) it
may be beneficial to cycle the intake air heater
twice before attempting to start the engine. This
can be accomplished by turning the ignition OFF
for at least 5 seconds and then back ON after
the “Wait To Start” telltale has turned off, but
before the engine is started. However, exces -
sive cycling of the intake air heater will result in
damage to the heater elements or reduced
battery voltage. NOTE:
If multiple pre-heat cycles are used before
starting, additional engine run time may be
required to maintain battery state of charge at a
satisfactory level.

1. If the engine stalls after the initial start, the
ignition must be turned to the OFF position
for at least five seconds and then to the ON
position to recycle the intake air heater.

NOTE:
Excessive white smoke and poor engine perfor -
mance will result if intake air heater are not
recycled.
2. Heat generated by the intake air heater dissipates rapidly in a cold engine. If more
than two minutes pass between the time
the “Wait To Start” telltale turns off and the
engine is started, recycle the intake air
heater by turning the ignition switch to the
OFF position for at least five seconds and
then back ON.
3. If the vehicle is driven and vehicle speed exceeds 19 mph (31 km/h) before the
intake air heater post-heat (after start) cycle
is complete, the intake air heater will shut
off. 4. If the engine is cranked for more than
10 seconds, the post-heat cycle will turn off.
NOTE:
Engine idle speed will automatically increase
to 1,000 RPM and engage the Variable
Geometry Turbocharger at low coolant
temperatures to improve engine warm-up.
When a diesel engine is allowed to run out of
fuel or the fuel gels at low temperatures, air
is pulled into the fuel system. If your engine
has run out of fuel, refer to “Dealer Service/
Priming If The Engine Has Run Out Of Fuel” in
“Servicing And Maintenance” for further
information.
If the engine stalls, or if the ignition switch is
left ON for more than two minutes after the
“Wait To Start” telltale goes out, reset the
intake air heater by turning the ignition
switch to the OFF position for at least 5
seconds and then back ON. Repeat steps
1 through 5 of “Starting Procedure – Engine
Manifold Air Temperature Below 66°F
(19°C).”

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224STARTING AND OPERATING
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 1000 RPM after starting with coolant
temperature below freezing conditions, and
may be limited to 1000 RPM for up to approxi -
mately 2 minutes under more severe cold
conditions.
NOTE:
If ambient temperatures are low and the
coolant temperature is below 180°F (82°C),
the engine idle speed will slowly increase to
1,000 RPM after two minutes of idle, if the
following conditions are met:
Foot is off brake pedal and throttle pedal.
Automatic transmission is in PARK.
Vehicle speed is 0 mph (0 km/h).
Applying the throttle will cancel fast idle.
Operating the exhaust brake at idle will
greatly improve warm up rate and will help
keep the engine close to operating tempera -
ture during extended idle.
Engine Idling
Avoid prolonged idling, long periods of idling
may be harmful to your engine because
combustion chamber temperatures can drop so
low that the fuel may not burn completely.
Incomplete combustion allows carbon and
varnish to form on piston rings, engine valves,
and injector nozzles. Also, the unburned fuel
can enter the crankcase, diluting the oil and
causing rapid wear to the engine.
If the engine is allowed to idle or the truck is
driven on low engine speed drive cycles for
more than 2 hours, the system will automati -
cally enter an emissions operating mode that
will increase the engine idle speed to 900 RPM.
While in this mode, which is designed to help
maintain the diesel particulate filter, the engine
idle speed will return to normal when the brake
pedal is applied. A small change in engine tone
or a slight change in engine performance while
accelerating may also be noticeable at speeds
below 20 mph (32 kmh). This operating mode
may last for up to an hour of idle time, or around
20 minutes of driving time.
Your truck may have been ordered with an
optional voltage monitoring idle up feature. If a
load is placed on the electrical system while the truck is in park, this feature will attempt to
maintain normal system voltage by automati
-
cally increasing engine idle speed. You may
notice several consecutive increases in idle
speed, up to a maximum of 1,450 RPM, as the
system will attempt to utilize the smallest
increase in idle speed necessary to maintain
normal system voltage. The idle speed will
return to normal when either the electrical load
is removed, or when the brake pedal is applied.
NOTE:
For instrument cluster display messages
related to the vehicle's exhaust system, refer to
“Instrument Cluster Display” in “Getting To
Know Your Instrument Panel” for further infor -
mation.
Idle-Up Feature
The driver-controlled high idle speed feature will
help increase cylinder temperatures and
provide additional cab heat, however, excessive
idling may still cause the exhaust aftertreat -
ment system to not properly regenerate.
Extended periods of idle time should be
avoided.
The Idle-Up feature uses the Speed Control
switches to increase engine idle speed and
quickly warm the vehicle's interior.

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STARTING AND OPERATING225

1. With the transmission in PARK, the parking
brake applied, and the engine running,
push the speed control switch to the ON
position, then push the SET switch.

2. The engine RPM will go up to 1,100 RPM. To increase the RPM, push and hold the
ACCEL/RESUME switch and the idle speed
will increase to approximately 1,500 RPM.
To decrease the RPM, push and hold the
DECEL switch and the idle speed will
decrease to approximately 1,100 RPM.
3. To cancel the Idle–Up feature, either push the CANCEL switch, push the ON/OFF
switch, or press the brake pedal.
Noise
Diesel engines can create noises that may
seem concerning. The nature of a diesel engine
is compression ignition where compressed air and fuel are mixed and ignited. Weather, baro
-
metric pressure, altitude, and temperature will
affect how fuel is ignited in the engine. Engines
will sound different from day to day or previous
model years. Clicking, ticking, or light knocking
is normal and will change from day to day, as
the engine breaks in, and can vary with changes
in ambient temperature. Clicking sound from
under the hood shortly after vehicle shutdown is
normal as actuators such as the EGR valve are
cycled. Fuel pump noise may increase during
low speed/light load conditions when ambient
temperature is above 100°F (38°C), and when
fuel tank level is below 10% which is a normal
condition of the fuel system and controls
strategy. Diesel equipped vehicles also have an
exhaust after-treatment system to reduce emis -
sions utilizing a DPF (refer to “Odor” in this
section for further information) and a Selective
Reduction Catalyst (SCR). The SCR reduces
Nitrogen Oxides (NOx) using the Diesel Exhaust Fluid (DEF) system. DEF is injected directly into
the SCR through a dosing module. This process
will create a clicking sound and at times, will
make noise even with the vehicle shut off. This
is normal as the DEF dosing module is purging
DEF. If at any time the check engine light is on,
please visit an authorized dealer.
Stopping The Engine
Idle the engine a few minutes before routine
shutdown. After full load operation, idle the
engine three to five minutes before shutting it
down. This idle period will allow the lubricating
oil and coolant to carry excess heat away from
the combustion chamber, bearings, internal
components, and turbocharger. This is espe
-
cially important for turbocharged, charge
air-cooled engines. Refer to the following chart
for proper engine shutdown:
Driving Condition Load Turbocharger Temperature Idle Time (min.) Before Engine
Shutdown
Stop and Go EmptyCoolLess than One
Stop and Go Medium -One
Highway Speeds MediumWarmTwo
5

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226STARTING AND OPERATING
Idle Shutdown
This feature can be enabled so that the truck
will automatically shutdown when the truck has
been idling for a set period of time when the
engine is at operating temperature. Idle time
can be set in 5 minute increments between 5
and 60 minutes. See an authorized dealer to
enable this feature.
NOTE:
The idle shut down timer is disabled while the
PTO is active.
Programmable Maximum Vehicle Speed
This feature allows the owner to set a maximum
vehicle speed for the vehicle. The 2500 and
3500 Series maximum vehicle speed can be set
between 40 mph (64 km/h) and 87 mph
(140 km/h). The 4500/5500 Series maximum
vehicle speed can be set between 40 mph (64 km/h) and 85 mph (136 km/h). See an
authorized dealer to enable this feature.
NOTE:
DO NOT set the maximum vehicle speed to a
value greater than what the vehicle tires are
rated for.
Operating Precautions
Avoid Overheating The Engine
The temperature of the engine coolant (anti
-
freeze) (a mixture of 50% ethylene-glycol and
50% water) must not exceed the normal range
of the temperature gauge 240°F (116°C) with
a 21 psi (145 kPa) coolant pressure cap.
Usually the engine coolant (antifreeze)
temperature indicated during operation will be
to the left of center in the normal range of the
gauge.
Avoid Low Coolant Temperature Operation
Continual operation at low engine coolant (anti -
freeze) temperature below the normal range on
the gauge 140°F (60°C) can be harmful to the
engine. Low engine coolant (antifreeze)
temperature can cause incomplete combustion
which allows carbon and varnish to form on
piston rings and injector nozzles. Also, the
unburned fuel can enter the crankcase, diluting
the lubricating oil and causing rapid wear to the
engine.
Cooling System Tips
To reduce potential for engine and transmission
overheating in high ambient temperature condi -
tions, take the following actions:
City Driving — When stopped, shift the trans -
mission into NEUTRAL and increase engine
idle speed.
Highway Driving — Reduce your speed.
City Traffic
Maximum GCWR -Three
Highway Speeds Maximum GCWR -Four
Uphill Grade Maximum GCWR HotFive
Driving Condition Load Turbocharger Temperature Idle Time (min.) Before Engine
Shutdown

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