2021 RAM CHASSIS CAB engine coolant

108GETTING TO KNOW YOUR INSTRUMENT PANEL
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
overheated 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 Ú
page 346.
Battery Charge Warning Light
This warning light will illuminate when
the battery is not charging properly.
If it stays on while the engine is
running, there may be a malfunction
with the charging system. Contact an
authorized dealer as soon as possible.
This indicates a possible problem with the
electrical system or a related component.
Oil Pressure Warning Light
This warning light will illuminate to
indicate low engine oil pressure. If the
light turns on while driving, stop the
vehicle, shut off the engine as soon as
possible, and contact an authorized dealer.
A chime will sound when this light turns on.
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.

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GETTING TO KNOW YOUR INSTRUMENT PANEL111
Electronic Stability Control (ESC) Active
Warning Light — If Equipped

This warning light will indicate when
the ESC system is Active. The ESC
Indicator Light in the instrument
cluster will come on when the ignition
is placed in the ON/RUN or ACC/ON/RUN
position, and when ESC is activated. It should go
out with the engine running. If the ESC Indicator
Light comes on continuously with the engine
running, a malfunction has been detected in
the ESC system. If this warning light remains
on after several ignition cycles, and the vehicle
has been driven several miles (kilometers) at
speeds greater than 30 mph (48 km/h), see an
authorized dealer as soon as possible to have the
problem diagnosed and corrected.

The ESC OFF Indicator Light and the ESC Indi -
cator Light come on momentarily each time
the ignition is placed in the ON/RUN or
ACC/ON/RUN position.
The ESC system will make buzzing or clicking
sounds when it is active. This is normal; the
sounds will stop when ESC becomes inactive.
This light will come on when the vehicle is in
an ESC event.
Electronic Stability Control (ESC) OFF
Warning Light — If Equipped
This warning light indicates the ESC is
off.
Each time the ignition is turned to ON/RUN or
ACC/ON/RUN, the ESC system will be on, even
if it was turned off previously.
Low Washer Fluid Warning Light — If
Equipped
This warning light will illuminate when
the windshield washer fluid is low
Ú page 364.
Low Fuel Warning Light
When the fuel level reaches
approximately 3.2 gal (12 L) this light
will turn on, and remain on until fuel is
added.
A single warning chime will sound with Low Fuel
Warning.
Low Coolant Level Warning Light
This telltale will turn on to indicate
the vehicle coolant level is low
Ú page 367.
Loose Fuel Filler Cap Warning Light — If
Equipped
This warning light will illuminate when
the fuel filler cap is loose. Properly
close the filler cap to disengage the
light. If the light does not turn off,
please see an authorized dealer.
Tire Pressure Monitoring System (TPMS)
Warning Light — If Equipped
The warning light switches on and a
message is displayed to indicate that
the tire pressure is lower than the
recommended value and/or that slow
pressure loss is occurring. In these cases,
optimal tire duration and fuel consumption may
not be guaranteed.
Should one or more tires be in the condition
mentioned above, the display will show the
indications corresponding to each tire.
3

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STARTING AND OPERATING125
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 6 of
“Keyless Enter-N-Go Starting Procedure –
Engine Manifold Air Temperature 0°F To 66°F
(–18°C to 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.
An intake air heater system both improves
engine starting and reduces the amount of
white smoke generated by a warming engine.
NORMAL STARTING PROCEDURE —
E
NGINE MANIFOLD AIR TEMPERATURE
A
BOVE 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
transmission. 3. Place the ignition switch in the ON position
and watch the instrument panel cluster
lights.
4. Place the ignition switch in the START position and crank the engine. Do not press
the accelerator during starting.
5. Check that the oil pressure warning light has turned off.
6. Release the parking brake.
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 Ú page 375.
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.

4

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126STARTING AND OPERATING
STARTING PROCEDURE — ENGINE
M
ANIFOLD 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 Ú page 90. When
engine temperatures fall below 66°F (19°C)
the “Wait To Start” telltale will remain on indi -
cating the intake air heater system is active.
Follow the steps in the “Normal Starting”
procedure 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
position. 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 ENGINE START/
STOP 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 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 0°F To 66°F (–18°C to 19°C).”

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 Ú
page 375.
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.

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STARTING AND OPERATING127
STARTING PROCEDURE — ENGINE
M
ANIFOLD 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 five seconds and then back ON after
the “Wait to Start” telltale has turned off, but
before the engine is started. However,
excessive 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 is 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 Ú
page 378.

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 0°F to 60°F (-18°C to 19°C).”

4

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STARTING AND OPERATING131
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.
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 two hours, the system will automatically
enter an emissions operating mode that will
increase the engine idle speed to 900 RPM
(1,050 RPM for Chassis Cab). 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 km/h). 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 automatically
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
Ú
page 90.
4

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STARTING AND OPERATING133
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 especially important for turbocharged, charge air-cooled engines. Refer to the following chart for proper
engine shutdown:
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 (Power Take-off) is active.
Driving Condition Load Turbocharger Temperature Idle Time (min.) Before Engine Shutdown
Stop and Go EmptyCool Less than One
Stop and Go Medium - One
Highway Speeds MediumWarm Two
City Traffic Maximum GCWR - Three
Highway Speeds Maximum GCWR - Four
Uphill Grade Maximum GCWR Hot Five
4

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134STARTING AND OPERATING
PROGRAMMABLE MAXIMUM VEHICLE
S
PEED
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 to 87 mph (64 km/h to
140 km/h). The 4500/5500 Series maximum
vehicle speed can be set between 40 mph to
85 mph (64 km/h to 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
(antifreeze: 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
(antifreeze) 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
conditions, take the following actions:
City Driving — When stopped, shift the trans
-
mission into NEUTRAL and increase engine
idle speed.
Highway Driving — Reduce your speed.
Up Steep Hills — Select a lower transmission
gear.
Air Conditioning — Turn it off temporarily.

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