2021 RAM CHASSIS CAB fuel cap

GETTING TO KNOW YOUR INSTRUMENT PANEL105
5 MPH Max Speed on Restart, Long Idle
or Refuel Service DEF See Dealer — This
message will continuously display when the
mileage 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 shutoff 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.
5 MPH Max Speed Service DEF System See
Dealer — This message will continuously
display, and will be accompanied by a peri -
odic chime. Although the vehicle can be
started and placed in gear, the vehicle will
only operate at a maximum speed of 5 mph.
Your vehicle will require towing, see an
authorized dealer for service.
NOTE:
When this message is displayed, the engine can
still be started. However, the vehicle will only
operate at a maximum speed of 5 mph.
Incorrect DEF Detected See Dealer — This
message will display when the fault is initially
detected, each time the vehicle is started,
and periodically during driving. The message
will be accompanied by a single chime.
We recommend you drive to the nearest
authorized dealer and have your vehicle
serviced as soon as possible.
RAM Active Air System

Your vehicle is equipped with an advanced
Ram Active Air system that provides enhanced
performance, especially when towing under
demanding hot or high altitude conditions. If the
instrument cluster display displays the message
“Active Airbox Service Required See Dealer”, vehicle
performance may be reduced until service is
performed by an authorized RAM dealer.

BATTERY SAVER ON/BATTERY SAVER
M
ODE MESSAGE — ELECTRICAL LOAD
R
EDUCTION ACTIONS — IF EQUIPPED
This vehicle is equipped with an Intelligent
Battery Sensor (IBS) to perform additional
monitoring of the electrical system and status
of the vehicle battery. In cases when the IBS detects charging system
failure, or the vehicle battery conditions are
deteriorating, electrical load reduction actions
will take place to extend the driving time and
distance of the vehicle. This is done by reducing
power to or turning off non-essential electrical
loads.
Load reduction is only active when the engine is
running. It will display a message if there is a
risk of battery depletion to the point where the
vehicle may stall due to lack of electrical supply,
or will not restart after the current drive cycle.
When load reduction is activated, the message
“Battery Saver On Some Systems May Have
Reduced Power” will appear in the instrument
cluster.
These messages indicate the vehicle battery
has a low state of charge and continues to lose
electrical charge at a rate that the charging
system cannot sustain.
3

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110GETTING TO KNOW YOUR INSTRUMENT PANEL
Door Open Warning Light
This indicator will illuminate when a
door is ajar/open and not fully closed.
NOTE:
If the vehicle is moving there will also be a single
chime.
YELLOW WARNING LIGHTS
Adaptive Cruise Control (ACC) Fault
Warning Light — If Equipped
This warning light will illuminate to
indicate a fault in the ACC system.
Contact a local authorized dealer for
service Ú page 166.
Engine Check/Malfunction Indicator
Warning Light (MIL)
The Engine Check/Malfunction
Indicator Light (MIL) is a part of an
Onboard Diagnostic System called
OBD II that monitors engine and
automatic transmission control systems. This
warning light will illuminate when the ignition
is in the ON/RUN position before engine start.
If the bulb does not come on when turning the
ignition switch from OFF to ON/RUN, have the
condition checked promptly.
Certain conditions, such as a loose or missing
gas cap, poor quality fuel, etc., may illuminate
the light after engine start. The vehicle should
be serviced if the light stays on through several
typical driving styles. In most situations, the
vehicle will drive normally and will not require
towing.
When the engine is running, the MIL may flash
to alert serious conditions that could lead to
immediate loss of power or severe catalytic
converter damage. The vehicle should be
serviced by an authorized dealer as soon as
possible if this occurs.
CAUTION!
Continuous driving with the Transmission
Temperature Warning Light illuminated will
eventually cause severe transmission
damage or transmission failure.
WARNING!
A malfunctioning catalytic converter, as
referenced above, can reach higher
temperatures than in normal operating
conditions. This can cause a fire if you drive
slowly or park over flammable substances
such as dry plants, wood, cardboard, etc.
This could result in death or serious injury to
the driver, occupants or others.
CAUTION!
Prolonged driving with the Malfunction
Indicator Light (MIL) on could cause damage
to the vehicle control system. It also could
affect fuel economy and driveability. If the
MIL is flashing, severe catalytic converter
damage and power loss will soon occur.
Immediate service is required.

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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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130STARTING AND OPERATING
NOTE:
Use of Climatized ULSD or Number 1 ULSD
Fuel results in a noticeable decrease in fuel
economy.

Climatized ULSD Fuel is a blend of Number 2
ULSD and Number 1 ULSD Fuels which
reduces the temperature at which wax crystals
form in fuel.

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 433.
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 temperature present. This may
occur on an unseasonably 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
Úpage 367.
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 Volts 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.

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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.

21_DPF_OM_EN_USC_t.book Page 134

STARTING AND OPERATING135
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.
DIESEL PARTICULATE FILTER (DPF)
M
ANUAL REGENERATION - IF EQUIPPED
On equipped Chassis Cabs, a manual
regeneration can be enable through the
instrument cluster. The manual regeneration
will allow the DPF to complete a regeneration,
lowering the soot level without having to drive
the vehicle. The vehicle must be in PARK to
access this feature, and the fuel level must be
over 12.5% full. A message displaying the time
left on the regeneration will appear on the
instrument cluster, and the instrument cluster
will display the soot level Ú page 90.
ENGINE BLOCK HEATER — IF EQUIPPED
The engine block heater warms the engine, and
permits quicker starts in cold weather. Connect
the cord to a standard 110-115 Volt AC
electrical outlet with a grounded, three-wire
extension cord.
Gas Engine Only
The engine block heater cord is routed through
the grille by the right front tow hook.
It includes a removable cap that is secured by a
tethered strap. It also has a c-clip that is used
for storage when not in use for the Winter
months. During Winter months, remove the
heater cord wiring assembly from itself on the
c-clip.
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.4

21_DPF_OM_EN_USC_t.book Page 135

STARTING AND OPERATING195
ENGINE RUNAWAY
Diesel engine runaway is a rare condition
affecting diesel engines, where the engine
consumes its own lubrication oil and runs at
higher and higher RPM until it overspeeds to
a point where it destroys itself due to either
mechanical failure or engine seizure through
lack of lubrication.
REFUELING THE VEHICLE — GASOLINE
ENGINE
NOTE:
When the fuel nozzle “clicks” or shuts off the
fuel tank is full. NOTE:
Tighten the gas cap a quarter turn until you hear
one click. This is an indication that the cap is
properly tightened.
If the gas cap is not tightened properly, the
Malfunction Indicator Light will come on.
Be sure the gas cap is tightened every time the
vehicle is refueled.
WARNING!
In case of engine runaway due to flammable
fumes from fuel spills or turbocharger oil
leaks being sucked into the engine, do the
following to help avoid personal injury and/or
vehicle damage:
Turn the ignition switch to the OFF position.

Using a CO2 or dry chemical type fire extin
-
guisher, direct the spray from the fire extin -
guisher into the grille on the passenger side so
that the spray enters the engine air intake.

The inlet for the engine air intake is located
behind the passenger side headlamp and
receives air through the grille.
CAUTION!
Damage to the fuel system or emissions
control system could result from using an
improper fuel tank filler tube cap (fuel filler
cap). A poorly fitting cap could let impurities
into the fuel system. Also, a poorly-fitted
aftermarket cap can cause the MIL
(Malfunction Indicator Light) to illuminate
due to fuel vapors escaping from the
system.
A poorly fitting fuel filler cap may cause the
MIL to turn on.
To avoid fuel spillage and overfilling, do not
“top off” the fuel tank after filling.
WARNING!
Never have any smoking materials lit in
or near the vehicle when the gas cap is
removed or the tank is being filled.
Never add fuel to the vehicle when the
engine is running. This is in violation of
most state and federal fire regulations and
may cause the MIL to turn on.
WARNING!
A fire may result if gasoline is pumped into a
portable container that is inside of a vehicle.
You could be burned. Always place gas
containers on the ground while filling.
4

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196STARTING AND OPERATING
LOOSE FUEL FILLER CAP MESSAGE
If the vehicle diagnostic system
determines that the fuel filler cap
is loose, improperly installed, or
damaged, a loose gASCAP indicator
will display in the instrument cluster telltale
display area Ú page 90. Tighten the fuel filler
cap properly and push the RIGHT button to turn
off the message. If the problem continues, the
message will appear the next time the vehicle is
started.
REFUELING THE VEHICLE — DIESEL ENGINE
NOTE:
When the fuel nozzle “clicks” or shuts off, the
fuel tank is full.
Tighten the fuel filler cap until you hear a
“clicking” sound. This is an indication that the
fuel filler cap is properly tightened.
Make sure that the fuel filler cap is tightened
each time the vehicle is refueled.
DIESEL EXHAUST FLUID
Your vehicle is equipped with a Selective
Catalytic Reduction (SCR) system to meet the
very stringent diesel emissions standards
required by the Environmental Protection
Agency.

The purpose of the SCR system is to reduce levels
of NOx (oxides of nitrogen emitted from engines)
that are harmful to our health and the
environment to a near-zero level. A small quantity
of Diesel Exhaust Fluid (DEF) is injected into the
exhaust upstream of a catalyst where, when
vaporized, it converts smog-forming nitrogen
oxides (NOx) into harmless nitrogen (N2) and
water vapor (H2O), two natural components of
the air we breathe. You can operate with the
comfort that your vehicle is contributing to a
cleaner, healthier world environment for this and
generations to come.

System Overview
This vehicle is equipped with a Diesel Exhaust
Fluid (DEF) injection system and a Selective
Catalytic Reduction (SCR) catalyst to meet the
emission requirements.
The DEF injection system consists of the
following components:
DEF tank
DEF pump
DEF injector
Electronically-heated DEF lines
DEF control module
NOx sensors
Temperature sensors
SCR catalyst
UQS Sensor
For system messages and warnings Úpage 90.
CAUTION!
To avoid fuel spillage and overfilling, do not
“top off” the fuel tank after filling.
WARNING!
A fire may result if gasoline is pumped into a
portable container that is inside of a vehicle.
You could be burned. Always place gas
containers on the ground while filling.

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