2023 RAM CHASSIS CAB coolant

120STARTING AND OPERATING
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.
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 89. When
engine temperatures fall below 66°F (19°C) the
Wait To Start Indicator Light 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 Indicator Light will remain
on for a period of time that varies depending
on the engine temperature.

2. While the Wait To Start Indicator Light 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 Indicator Light 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 Indicator Light goes out, reset the intake
air heater by turning the ignition switch to the
OFF position for at least five seconds and then
back to the ON/RUN position. Repeat steps 1
through 5 of “Starting Procedure – Engine Mani -
fold Air Temperature 0°F To 66°F (–18°C to
19°C).”
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 Ú page 360.
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 OPERATING121
(Continued)
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 to OFF
position for at least five seconds and then back to
the ON/RUN position after the Wait To Start
Indicator Light 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/RUN
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 Indicator Light 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 to the ON/RUN position.
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 363.
If the engine stalls, or if the ignition switch is left
on for more than two minutes after the Wait To
Start Indicator Light goes out, reset the intake
air heater by turning the ignition switch to the
OFF position for at least five seconds and then
back to the ON/RUN position. Repeat steps 1
through 5 of “Starting Procedure – Engine Mani -
fold Air Temperature 0°F to 60°F (-18°C to
19°C).”
STARTING FLUIDS
The engine is equipped with an automatic electric
air preheating system. If the instructions in this
manual are followed, the engine should start in all
conditions.
WARNING!
Starting fluids or flammable liquids must never
be used in the Cummins® diesel engine (see
Warning label). Never pour diesel fuel,
flammable liquid, starting fluids (ether) into the
air cleaner canister, air intake piping, or
turbocharger inlet in an attempt to start the
vehicle. This could result in a flash fire and
explosion causing serious personal injury and
engine damage.
WARNING!
Do not leave children or animals inside parked
vehicles in hot weather. Interior heat build-up
may cause serious injury or death.
When leaving the vehicle, always remove the
key fob and lock your vehicle.
4

23_DPF_OM_EN_USC_t.book Page 121

STARTING AND OPERATING123
The fuel grade should be clearly marked on the
pump at the fuel station.
The engine requires the use of ULSD Fuel. Use
of incorrect fuel could result in engine and
exhaust system damage Ú page 413.
If climatized or diesel Number 1 ULSD Fuel is
not available, and you are operating below
(20°F/-6°C), in sustained arctic conditions,
Mopar® Premium Diesel Fuel Treatment (or
equivalent) is recommended to avoid gelling
(see Fuel Operating Range Chart).
Under some circumstances increased engine
noise may be audible in the seconds following a
cold start. This is most likely to occur when using
fuel that isn't blended for the ambient tempera -
ture present. This may occur on an unseason -
ably cold day or when a truck is fueled in a
warmer climate and driven to a colder climate.
The noise can typically be prevented by using
Mopar® Premium Diesel Fuel Treatment as
recommended (see Fuel Operating Range
Chart).
Engine Oil Usage
For the correct engine oil viscosity Ú page 353.
Winter Front Cover Usage
A Winter front or cold weather cover is to be used
in ambient temperatures below 32°F (0°C),
especially during extended idle conditions. This
cover is equipped with four flaps for managing total grille opening in varying ambient
temperatures. If a Winter front or cold weather
cover is to be used the flaps should be left in the
full open position to allow air flow to the charge air
cooler and automatic transmission oil cooler.
When ambient temperatures drop below 0°F
(-17°C) the four flaps need to be closed. A suitable
cold weather cover is available from a Mopar®
dealer.
Battery Blanket Usage
A battery loses 60% of its cranking power as the
battery temperature decreases to 0°F (-18°C). For
the same decrease in temperature, the engine
requires twice as much power to crank at the same
RPM. The use of 120 Volt AC powered battery
blankets will greatly increase starting capability at
low temperatures. Suitable battery blankets are
available from an authorized Mopar® dealer.
Engine Warm-Up
Avoid full throttle operation when the engine is
cold. When starting a cold engine, bring the engine
up to operating speed slowly to allow the oil
pressure to stabilize as the engine warms up.
NOTE:High-speed, no-load running of a cold engine can
result in excessive white smoke and poor engine
performance. No-load engine speeds should be
kept under 1,000 RPM during the warm-up period,
especially in cold ambient temperature conditions.
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 accelerator pedal.
Automatic transmission is in PARK.
Vehicle speed is 0 mph (0 km/h).
Applying the accelerator pedal 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 temperature during
extended idle.
4

23_DPF_OM_EN_USC_t.book Page 123

STARTING AND OPERATING125
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 Power Take Off (PTO) is active.
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
City Traffic Maximum GCWR -Three
Highway Speeds Maximum GCWR -Four
Uphill Grade Maximum GCWR HotFive
4

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126STARTING 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 transmis
-
sion 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.
Do Not Operate The Engine With Low Oil
Pressure
When the engine is at normal operating
temperature, the minimum oil pressures required
are:
Do Not Operate The Engine With Failed
Parts
All engine failures give some warning before the
parts fail. Be on the alert for changes in
performance, sounds, and visual evidence that the
engine requires service. Some important clues are:
Engine misfiring or vibrating severely.
Sudden loss of power.
Unusual engine noises.
Fuel, oil or coolant leaks.
Sudden change, outside the normal operating
range, in the engine operating temperature.
Excessive smoke.
Oil pressure drop.
Idle 700 to 800 RPM 10 psi (69 kPa)
Full speed and load 30 psi (207 kPa)
CAUTION!
If oil pressure falls to less than normal readings,
shut the engine off immediately. Failure to do so
could result in immediate and severe engine
damage.

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128STARTING AND OPERATING
ENGINE BREAK-IN RECOMMENDATIONS —
DIESEL ENGINE
The Cummins® Turbo Diesel engine does not
require a break-in period due to its construction.
Normal operation is allowed, providing the
following recommendations are followed:
Warm up the engine before placing it under
load.
Do not operate the engine at idle for prolonged
periods.
Use the appropriate transmission gear to
prevent engine lugging.
Observe vehicle oil pressure and temperature
indicators.
Check the coolant and oil levels frequently.
Vary throttle position at highway speeds when
carrying or towing significant weight.
NOTE:Light duty operation such as light trailer towing or
no load operation will extend the time before the
engine is at full efficiency. Reduced fuel economy
and power may be seen at this time.
For additional vehicle break-in requirements
Úpage 186. Because of the construction of the Cummins®
Turbo Diesel engine, engine run-in is enhanced by
loaded operating conditions which allow the
engine parts to achieve final finish and fit during
the first 6,000 miles (10,000 km).
PARKING BRAKE
Before leaving the vehicle, make sure that the
parking brake is fully applied. Also, be certain to
leave the transmission in PARK.
The foot operated parking brake is located below
the lower left corner of the instrument panel. To
apply the parking brake, firmly push the parking
brake pedal fully. To release the parking brake, pull
the parking brake release handle.

Parking Brake Release
When the parking brake is applied with the ignition
switch ON, the Brake Warning Light in the
instrument cluster will illuminate.
NOTE:
When the parking brake is applied and the
transmission is placed in gear, the Brake
Warning Light will flash. If vehicle speed is
detected, a chime will sound to alert the driver.
Fully release the parking brake before
attempting to move the vehicle.
This light only shows that the parking brake is
applied. It does not show the degree of brake
application.
When parking on a hill, it is important to turn the
front wheels toward the curb on a downhill grade
and away from the curb on an uphill grade. Apply
the parking brake before placing the gear selector
in PARK, otherwise the load on the transmission
locking mechanism may make it difficult to move
the gear selector out of PARK. The parking brake
should always be applied whenever the driver is
not in the vehicle.

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130STARTING AND OPERATING
(Continued)
(Continued)
NOTE:For optimum braking power it is recommended to
use the exhaust brake while in TOW/HAUL mode.
The exhaust brake feature can also be used to
reduce the engine warm-up time. To use the
exhaust brake as a warm-up device, the vehicle
must be stopped or moving less than 5 mph
(8 km/h), the Exhaust Brake Indicator must be on,
and the coolant temperature must be below
180°F (82°C) and ambient temperature below
60°F (16°C).
Automatic “Smart” Exhaust Brake
Automatic “Smart” Exhaust Brake technology
delivers smoother, less aggressive exhaust
braking characteristics during downhill descents.
Although it can apply full exhaust braking force if
needed, Automatic “Smart” Exhaust Brake may
not apply obvious braking if the vehicle speed is
not increasing. Automatic “Smart” Exhaust Brake
is intended to maintain vehicle speed, while Full
Exhaust Brake is intended to reduce vehicle speed. Automatic “Smart” Exhaust Brake can be enabled
by pushing the exhaust brake button (on the center
stack) again anytime after the normal Full Exhaust
Brake has been turned on. The Exhaust Brake
Indicator in the instrument cluster display will
change from Yellow to Green when Automatic
“Smart” Exhaust Brake is enabled. Pushing the
exhaust brake button again will toggle the exhaust
brake mode to off.
AUTOMATIC TRANSMISSION
You must press and hold the brake pedal while
shifting out of PARK.
CAUTION!
Use of aftermarket exhaust brakes is not
recommended and could lead to engine
damage.
WARNING!
It is dangerous to shift out of PARK or
NEUTRAL if the engine speed is higher than
idle speed. If your foot is not firmly pressing
the brake pedal, the vehicle could accelerate
quickly forward or in reverse. You could lose
control of the vehicle and hit someone or
something. Only shift into gear when the
engine is idling normally and your foot is firmly
pressing the brake pedal.
The transmission may not engage PARK if the
vehicle is moving. Always bring the vehicle to a
complete stop before shifting to PARK, and
verify that the transmission gear position indi
-
cator solidly indicates PARK (P) without
blinking. Ensure that the vehicle is completely
stopped, and the PARK position is properly
indicated, before exiting the vehicle.
Unintended movement of a vehicle could
injure those in or near the vehicle. As with all
vehicles, you should never exit a vehicle while
the engine is running. Before exiting a vehicle,
always come to a complete stop, then apply
the parking brake, shift the transmission into
PARK, turn the engine OFF, and remove the
key fob. When the ignition is in the LOCK/OFF
(key removal) position, (or, with Keyless Enter
‘n Go™, when the ignition is in the OFF posi -
tion) the transmission is locked in PARK,
securing the vehicle against unwanted move -
ment.
When leaving the vehicle, always make sure
the ignition is in the OFF position, remove the
key fob from the vehicle, and lock the vehicle.
WARNING!

23_DPF_OM_EN_USC_t.book Page 130

138STARTING AND OPERATING
You can switch between DRIVE and ERS mode at
any vehicle speed. When the gear selector is in the
DRIVE position, the transmission will operate
automatically, shifting between all available gears.
Tapping the ERS “-” switch will activate ERS mode,
display the current gear in the instrument cluster,
and set that gear as the top available gear. Once in
ERS mode, tapping “-” or “+” will change the top
available gear.

Electronic Range Select

To exit ERS mode, simply push and hold the
ERS “+” switch until the gear limit display
disappears from the instrument cluster.
NOTE:To select the proper gear position for maximum
deceleration (engine braking), simply push and
hold the ERS “-” switch. The transmission will shift
to the range from which the vehicle can best be
slowed down.
Overdrive Operation

The automatic transmission includes an
electronically controlled Overdrive (FIFTH and SIXTH
gears). The transmission will automatically shift into
Overdrive if the following conditions are present:

The gear selector is in the DRIVE position.
The transmission fluid has reached an
adequate temperature.
The engine coolant has reached an adequate
temperature.
Vehicle speed is sufficiently high.
The TOW/HAUL switch has not been activated.
The driver is not heavily pressing the acceler -
ator.
When To Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer, carrying
a heavy load, etc., and frequent transmission
shifting occurs, push the TOW/HAUL switch to
activate TOW/HAUL mode. This will improve
performance and reduce the potential for
transmission overheating or failure due to
excessive shifting. When operating in TOW/HAUL
mode, transmission upshifts are delayed, and the
transmission will automatically downshift (for
engine braking) when the throttle is closed and/or
during steady braking maneuvers.

TOW/HAUL Switch

1 — GEAR “+” Switch
2 — GEAR “–” Switch
WARNING!
Do not downshift for additional engine braking
on a slippery surface. The drive wheels could
lose their grip and the vehicle could skid,
causing a collision or personal injury.
CAUTION!
When using ERS for engine braking while
descending steep grades, be careful not to
overspeed the engine. Apply the brakes as
needed to prevent engine overspeed.

23_DPF_OM_EN_USC_t.book Page 138