2021 RAM 1500 heater

146STARTING AND OPERATING
(Continued)
COLD WEATHER OPERATION (BELOW
–22°F O
R −30°C)
To ensure reliable starting at these
temperatures, use of an externally powered
electric engine block heater (available from an
authorized dealer) is recommended.
AFTER STARTING
The idle speed is controlled automatically, and
it will decrease as the engine warms up.
STARTING FLUIDS — DIESEL ENGINE
O
NLY
The engine is equipped with a glow plug
preheating system. If the instructions in this
manual are followed, the engine should start in
all conditions and no type of starting fluid
should be used.
NORMAL OPERATION — DIESEL ENGINE
Observe the following when the diesel engine is
operating.
All message center lights are off.
Malfunction Indicator Light (MIL) is off.
Engine Oil Pressure telltale is not illuminated.
Voltmeter operation:
The voltmeter may show a gauge fluctuation at
various engine temperatures. This is caused by
the glow plug heating system. The number of
cycles and the length of the cycling operation is
controlled by the engine control module. Glow
plug heater operation can run for several
minutes, once the heater operation is complete
the voltmeter needle will stabilize.
COLD WEATHER PRECAUTIONS
Operation in ambient temperature below 32°F
(0°C) may require special considerations. The
following charts suggest these options:
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 make
sure the wireless ignition node is in the
“OFF” mode, remove the key fob from the
vehicle and lock the vehicle.
Never leave children alone in a vehicle, or
with access to an unlocked vehicle.
Allowing children to be in a vehicle unat -
tended is dangerous for a number of
reasons. A child or others could be seriously
or fatally injured. Children should be
warned not to touch the parking brake,
brake pedal or the gear selector.
Do not leave the key fob in or near the
vehicle, or in a location accessible to chil-
dren, and do not leave the ignition of a
vehicle equipped with Keyless Enter-N-Go
in the ACC or ON/RUN mode. A child could
operate power windows, other controls, or
move the vehicle.
WARNING! (Continued)

21_DT_OM_EN_USC_t.book Page 146

150STARTING AND OPERATING
ENGINE BLOCK HEATER — IF EQUIPPED

Engine Block Heater Cord Location

The engine block heater warms engine coolant
and permits quicker starts in cold weather.
Connect the heater cord to a ground-fault
interrupter protected 110–115 Volt AC
electrical outlet with a grounded, three-wire
extension cord.
For diesel engines, its use is recommended for
environments that routinely fall below -10°F
(-23°C). It should be used when the vehicle has
not been running for long periods of time and
should be plugged in two hours prior to start. Its
use is required for cold starts with temperatures
under -20°F (-28°C). To ensure reliable starting at these
temperatures, use of an externally powered
electric engine block heater (available from an
authorized dealer) is recommended.
The engine block heater cord is routed under
the hood on the passenger side of the vehicle
next to the engine coolant reservoir.
ENGINE BREAK-IN RECOMMENDATIONS —
GASOLINE ENGINE
A long break-in period is not required for the
engine and drivetrain (transmission and axle) in
your vehicle.
Drive moderately during the first 300 miles
(500 km). After the initial 60 miles (100 km),
speeds up to 50 or 55 mph (80 or 90 km/h) are
desirable.
While cruising, brief full-throttle acceleration
within the limits of local traffic laws contributes
to a good break-in. Wide-open throttle
acceleration in low gear can be detrimental and
should be avoided.
The engine oil installed in the engine at the
factory is a high-quality energy conserving type
lubricant. Oil changes should be consistent with
anticipated climate conditions under which
vehicle operations will occur. For the
recommended viscosity and quality grades
Ú
page 475.
NOTE:
A new engine may consume some oil during its
first few thousand miles (kilometers) of opera -
tion. This should be considered a normal part of
the break-in and not interpreted as a problem.
Please check your oil level with the engine oil
indicator often during the break in period. Add
oil as required.
WARNING!
Remember to disconnect the engine block
heater cord before driving. Damage to the
110-115 Volt electrical cord could cause
electrocution.
CAUTION!
Never use Non-Detergent Oil or Straight
Mineral Oil in the engine or damage may
result.

21_DT_OM_EN_USC_t.book Page 150

STARTING AND OPERATING211
DIESEL EXHAUST FLUID
Your vehicle is equipped with a Selective
Catalytic Reduction (SCR) system to meet diesel
emissions standards required by the
Environmental Protection Agency.
The purpose of the SCR system is to reduce
levels of oxides of nitrogen (NO
x) 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, converts smog-forming
NO
x into harmless nitrogen (N2) and water
vapor (H
2O), two natural components of the air
we breathe.
DIESEL EXHAUST FLUID STORAGE
Diesel Exhaust Fluid (DEF) is considered a very
stable product with a long shelf life. If DEF is
kept in temperatures between 10° and 90°F
(-12° and 32°C), it will last a minimum of one
year.
DEF may freeze at temperatures at or below
12°F (-11°C). The system has been designed to
operate in this environment. NOTE:
When working with DEF, it is important to know
that:
Any containers or parts that come into
contact with DEF must be DEF compatible
(plastic or stainless steel). Copper, brass,
aluminum, iron or non-stainless steel should
be avoided as they are subject to corrosion
by DEF.
If DEF is spilled, it should be wiped up
completely.
ADDING DIESEL EXHAUST FLUID
The Diesel Exhaust Fluid (DEF) gauge (located
on the instrument cluster) will display the level
of DEF remaining in the tank Ú
page 109.
NOTE:
Driving conditions (altitude, vehicle speed,
load, etc.) will effect the amount of DEF that
is used in your vehicle.
Outside temperature can affect DEF
consumption. In cold conditions, 12°F
(-11°C) and below, the DEF gauge may take
longer to operate as intended. This is a
normal function of the system.
There is an electric heater inside the DEF
tank that automatically works when neces -
sary. And if the DEF supply does freeze, the
truck will operate normally until it thaws.
Diesel Exhaust Fluid (DEF) Fill Procedure
NOTE:
For the correct fluid type Ú page 475.

1. Remove cap from Diesel Exhaust Fluid (DEF) tank which is located next to the
diesel fuel filler.

DEF Filler Cap And Fuel Fill

1 — Diesel Exhaust Fluid (DEF) Fill Location
2 — Diesel Fuel Fill Location
4

21_DT_OM_EN_USC_t.book Page 211

212STARTING AND OPERATING
(Continued)
(Continued)
2. Insert DEF fill adapter/nozzle into DEF tank filler neck.
NOTE:
The DEF gauge may take up to five seconds
to update after adding a gallon or more of
(DEF) to the DEF tank. If you have a fault
related to the DEF system, the gauge may not
update to the new level. See an authorized
dealer for service.
The DEF gauge may also not immediately
update after a refill if the temperature of the
DEF fluid is below 12°F (-11°C). The DEF line
heater will possibly warm up the DEF fluid
and allow the gauge to update after a period
of run time. Under very cold conditions, it is
possible that the gauge may not reflect the
new fill level for several drives.
Refilling With Nozzles
You can fill up at any DEF distributor.
Proceed as follows:
Insert the DEF nozzle in the filler, start
refilling and stop refilling at the first
shut-off (the shut-off indicates that the
DEF tank is full). Do not proceed with the
refilling, to prevent spillage of DEF.
Extract the nozzle. Refilling With Containers
Proceed as follows:
Check the expiration date.
Read the advice for use on the label
before pouring the content of the bottle
into the DEF tank.
If systems which cannot be screwed in
(e.g. tanks) are used for refilling, after the
indication appears on the instrument
panel display Ú
page 114 fill the DEF
tank with no more than 2 Gallons (8
liters).
If containers which can be screwed to the
filler are used, the reservoir is full when
the DEF level in the container stops
pouring out. Do not proceed further.
CAUTION!
To avoid DEF spillage, and possible
damage to the DEF tank from overfilling, do
not “top off” the DEF tank after filling.
DO NOT OVERFILL. DEF will freeze below
12ºF (-11ºC). The DEF system is designed
to work in temperatures below the DEF
freezing point, however, if the tank is over -
filled and freezes, the system could be
damaged.
When DEF is spilled, clean the area imme -
diately with water and use an absorbent
material to soak up the spills on the ground.
Do not attempt to start your engine if DEF is
accidentally added to the diesel fuel tank
as it can result in severe damage to your
engine, including but not limited to failure
of the fuel pump and injectors.
CAUTION! (Continued)

21_DT_OM_EN_USC_t.book Page 212

SAFETY353
eye irritation, rinse the area with cool water.
For nose or throat irritation, move to fresh air.
If the irritation continues, see your doctor. If
these particles settle on your clothing, follow
the garment manufacturer’s instructions for
cleaning.
Do not drive your vehicle after the air bags have
deployed. If you are involved in another
collision, the air bags will not be in place to
protect you.
NOTE:
Air bag covers may not be obvious in the inte -
rior trim, but they will open during air bag
deployment.
After any collision, the vehicle should be
taken to an authorized dealer immediately.
Enhanced Accident Response System
In the event of an impact, if the communication
network remains intact, and the power remains
intact, depending on the nature of the event,
the Occupant Restraint Controller (ORC) will
determine whether to have the Enhanced
Accident Response System perform the
following functions:
Cut off fuel to the engine (if equipped)
Cut off battery power to the electric motor (if
equipped)
Flash hazard lights as long as the battery has
power
Turn on the interior lights, which remain on
as long as the battery has power or for
15 minutes from the intervention of the
Enhanced Accident Response System
Unlock the power door locks
Your vehicle may also be designed to perform
any of these other functions in response to the
Enhanced Accident Response System:
Turn off the Fuel Filter Heater, Turn off the
HVAC Blower Motor, Close the HVAC Circula -
tion Door
Cut off battery power to the:
Engine
Electric Motor (if equipped)
Electric power steering
Brake booster
Electric park brake
Automatic transmission gear selector
Horn
Front wiper
Headlamp washer pump
NOTE:
After an accident, remember to cycle the igni -
tion to the STOP (OFF/LOCK) position and
remove the key from the ignition switch to avoid
draining the battery. Carefully check the vehicle
for fuel leaks in the engine compartment and on
the ground near the engine compartment and
fuel tank before resetting the system and
starting the engine. If there are no fuel leaks or
damage to the vehicle electrical devices (e.g.
headlights) after an accident, reset the system
by following the procedure described below. If
you have any doubt, contact an authorized
dealer.
WARNING!
Deployed air bags and seat belt
pretensioners cannot protect you in another
collision. Have the air bags, seat belt
pretensioners, and the seat belt retractor
assemblies replaced by an authorized dealer
immediately. Also, have the Occupant
Restraint Controller System serviced as well.
6

21_DT_OM_EN_USC_t.book Page 353

IN CASE OF EMERGENCY387

Positive Battery Post

See below steps to prepare for jump starting:

1. Apply the parking brake, shift the automatic transmission into PARK and
turn the ignition OFF.

2. Turn off the heater, radio, and all electrical accessories.
3. Pull upward and remove the protective cover over the remote positive (+) battery
post.
4. If using another vehicle to jump start the battery, park the vehicle within the jumper
cables’ reach, apply the parking brake and
make sure the ignition is OFF.
JUMP STARTING PROCEDURE
Connecting The Jumper Cables

Jumper Cable Connections

WARNING!
Take care to avoid the radiator cooling fan
whenever the hood is raised. It can start
anytime the ignition switch is ON. You can
be injured by moving fan blades.
Remove any metal jewelry such as rings,
watch bands and bracelets that could
make an inadvertent electrical contact. You
could be seriously injured.
Batteries contain sulfuric acid that can
burn your skin or eyes and generate
hydrogen gas which is flammable and
explosive. Keep open flames or sparks
away from the battery.
WARNING!
Do not allow vehicles to touch each other as
this could establish a ground connection and
personal injury could result.
WARNING!
Failure to follow this jump starting procedure
could result in personal injury or property
damage due to battery explosion.
CAUTION!
Failure to follow these procedures could
result in damage to the charging system of
the booster vehicle or the discharged vehicle.
7

21_DT_OM_EN_USC_t.book Page 387

IN CASE OF EMERGENCY389
REFUELING IN EMERGENCY – IF EQUIPPED
The fuel filling procedure in case of an
emergency is described on Ú page 208.
The vehicle is equipped with a refueling funnel.
If refueling is necessary, while using an
approved gas can, please insert the refueling
funnel into the filler neck opening.

Refueling FunnelInserting Funnel

IF YOUR ENGINE OVERHEATS
If the vehicle is overheating, it will need to be
serviced by an authorized dealer.
In any of the following situations, you can
reduce the potential for overheating by taking
the appropriate action.
On the highways — slow down.
In city traffic — while stopped, place the trans -
mission in NEUTRAL (N), but do not increase
the engine idle speed while preventing
vehicle motion with the brakes.
NOTE:
There are steps that you can take to slow down
an impending overheat condition:
If your Air Conditioner (A/C) is on, turn it off.
The A/C system adds heat to the engine
cooling system and turning the A/C off can
help remove this heat.
You can also turn the temperature control to
maximum heat, the mode control to floor and
the blower control to high. This allows the
heater core to act as a supplement to the
radiator and aids in removing heat from the
engine cooling system.
WARNING!
You or others can be badly burned by hot
engine coolant (antifreeze) or steam from
your radiator. If you see or hear steam coming
from under the hood, do not open the hood
until the radiator has had time to cool. Never
try to open a cooling system pressure cap
when the radiator or coolant bottle is hot.
CAUTION!
Driving with a hot cooling system could
damage your vehicle. If the temperature
gauge reads HOT (H), pull over and stop the
vehicle. Idle the vehicle with the air
conditioner turned off until the pointer drops
back into the normal range. If the pointer
remains on HOT (H), and you hear continuous
chimes, turn the engine off immediately and
call for service.
7

21_DT_OM_EN_USC_t.book Page 389

430SERVICING AND MAINTENANCE
F2650 Amp Red –ESP Module
F27 30 Amp Pink –Front Wiper
F28 –10 Amp Red PCM / ECM
F29 40 Amp Green –ESP Module
F30 ––Spare
F31 ––Spare
F32 20 Amp Blue –ECM / PCM
F33 30 Amp Pink –Brake Vacuum Pump
F34 ––Spare
F35 –10 Amp RedPCM / ECM / Power Pack Unit (PPU) Motor Generator Unit (MGU)
Wake Up / EPS / Active Tuned Mass Module (ATMM) / ESP
F36 ––Spare
F37 –5 Amp Tan R / S Output to iPDC
F38 –10 Amp Red DTCM / Active CL TEMP VLV
F39 –15 Amp Red MOD ATMM
F40 40 Amp Green –Starter
F41 –10 Amp Red IRCAM Heaters
F42 20 Amp Blue –AUX SWITCH #5 — If Equipped
F43 –20 Amp Yellow MGU Coolant Pump
F44 –10 Amp Red Trailer Camera
F45 –10 Amp Red ADCM — If Equipped
CavityCartridge Fuse Micro Fuse Description

21_DT_OM_EN_USC_t.book Page 430