lock RAM 1500 2021 Repair Manual

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

152STARTING AND OPERATING
(Continued)
NOTE:
The EPB fault light will illuminate if the EPB
switch is held for longer than 20 seconds in
either the released or applied position. The light
will extinguish upon releasing the switch.
If the Auto Park Brake feature is enabled, the
parking brake will automatically engage
whenever the transmission is placed into PARK.
If your foot is on the brake pedal, you may notice
a small amount of brake pedal movement while
the parking brake is engaging.
The parking brake will release automatically
when the ignition is ON, the transmission is in
DRIVE or REVERSE, the driver seat belt is
buckled, and an attempt is made to drive away.
To release the parking brake manually, the
ignition switch must be in the ON/RUN mode.
Put your foot on the brake pedal, then push the
parking brake switch down momentarily. You
may hear a slight whirring sound from the back
of the vehicle while the parking brake
disengages. You may also notice a small
amount of movement in the brake pedal. Once
the parking brake is fully disengaged, The
BRAKE telltale light in the instrument cluster
and the LED indicator on the switch will
extinguish.NOTE:
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.
WARNING!
Never use the PARK position as a substi
-
tute for the parking brake. Always apply the
parking brake fully when parked to guard
against vehicle movement and possible
injury or damage.
When exiting the vehicle, always remove
the key fob from the ignition and lock your
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 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.
Be sure the parking brake is fully disen -
gaged before driving; failure to do so can
lead to brake failure and a collision.
Always fully apply the parking brake when
leaving your vehicle, or it may roll and
cause damage or injury. Also be certain to
leave the transmission in PARK. Failure to
do so may allow the vehicle to roll and
cause damage or injury.
CAUTION!
If the Brake System Warning Light remains on
with the parking brake released, a brake
system malfunction is indicated. Have the
brake system serviced by an authorized
dealer immediately.
WARNING! (Continued)

21_DT_OM_EN_USC_t.book Page 152

STARTING AND OPERATING155
(Continued)
IGNITION PARK INTERLOCK
This vehicle is equipped with an Ignition Park
Interlock which requires the transmission to be
in PARK before the ignition can be turned to the
OFF mode. This helps the driver avoid
inadvertently leaving the vehicle without placing the transmission in PARK. This system also
locks the transmission in PARK whenever the
ignition is in the OFF mode.
NOTE:
The transmission is NOT locked in PARK when
the ignition is in the ACC mode (even though the
engine will be off). Ensure that the transmission
is in PARK, and the ignition is OFF (not in ACC
mode) before exiting the vehicle.
BRAKE/TRANSMISSION SHIFT
I
NTERLOCK SYSTEM
This vehicle is equipped with a Brake
Transmission Shift Interlock (BTSI) system that
holds the transmission gear selector in PARK
unless the brakes are applied. To shift the
transmission out of PARK, the engine must be
running and the brake pedal must be pressed.
The brake pedal must also be pressed to shift
from NEUTRAL into DRIVE or REVERSE when the
vehicle is stopped or moving at low speeds.
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, and turn the igni -
tion OFF. When the ignition is in the OFF
mode, the transmission is locked in PARK,
securing the vehicle against unwanted
movement.
When exiting the vehicle, always make sure
the ignition 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 transmission gear
selector.
WARNING! (Continued)
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 in the
ACC or ON/RUN mode. A child could
operate power windows, other controls, or
move the vehicle.
CAUTION!
Shift into or out of PARK or REVERSE only
after the vehicle has come to a complete
stop.
Do not shift between PARK, REVERSE,
NEUTRAL, or DRIVE when the engine is
above idle speed.
Before shifting into any gear, make sure
your foot is firmly pressing the brake pedal.
WARNING! (Continued)
4

21_DT_OM_EN_USC_t.book Page 155

156STARTING AND OPERATING
EIGHT-SPEED AUTOMATIC
T
RANSMISSION
The transmission is controlled using a rotary
electronic gear selector located on the
instrument panel. The transmission gear range
(PRND) is displayed both above the gear
selector and in the instrument cluster. To select
a gear range, simply rotate the gear selector.
You must press the brake pedal to shift the
transmission out of PARK (or NEUTRAL, when
the vehicle is stopped or moving at low speeds).
To shift past multiple gear ranges at once (such
as PARK to DRIVE), simply rotate the gear
selector to the appropriate detent. Select the
DRIVE range for normal driving.
NOTE:
In the event of a mismatch between the gear
selector position and the actual transmission
gear (for example, driver selects PARK while
driving), the position indicator will blink continu -
ously until the selector is returned to the proper
position, or the requested shift can be
completed. The electronically-controlled transmission
adapts its shift schedule based on driver inputs,
along with environmental and road conditions.
The transmission electronics are
self-calibrating; therefore, the first few shifts on
a new vehicle may be somewhat abrupt. This is
a normal condition, and precision shifts will
develop within a few hundred miles
(kilometers).
Only shift from DRIVE to PARK or REVERSE
when the accelerator pedal is released and the
vehicle is stopped. Be sure to keep your foot on
the brake pedal when shifting between these
gears.
The transmission gear selector has only PARK,
REVERSE, NEUTRAL, and DRIVE positions.
Manual downshifts can be made using the
Electronic Range Select (ERS) shift control.
Pressing the GEAR-/GEAR+ switches (on the
steering wheel) while in the DRIVE position will
select the highest available transmission gear,
and will display that gear limit in the instrument
cluster as 1, 2, 3, etc Ú
page 159. Some
models will display both the selected gear limit,
and the actual current gear, while in ERS mode.
Electronic Transmission Gear Selector

Gear Ranges
Do not press the accelerator pedal when
shifting from PARK or NEUTRAL into another
gear range.
NOTE:
After selecting any gear range, wait a moment
to allow the selected gear to engage before
accelerating. This is especially important when
the engine is cold.
PARK (P)
This range supplements the parking brake by
locking the transmission. The engine can be
started in this range. Never attempt to use PARK
while the vehicle is in motion. Apply the parking
brake when exiting the vehicle in this range.

21_DT_OM_EN_USC_t.book Page 156

STARTING AND OPERATING157
(Continued)
(Continued)
(Continued)
When parking on a hill, apply the parking brake
before shifting the transmission to PARK. As an
added precaution, turn the front wheels toward
the curb on a downhill grade and away from the
curb on an uphill grade.
NOTE:
On four-wheel drive vehicles be sure that the
transfer case is in a drive position.
When exiting the vehicle, always:
Apply the parking brake.
Shift the transmission into PARK.
Turn the engine off.
Remove the key fob from the vehicle.
WARNING!
Never use the PARK position as a substi
-
tute for the parking brake. Always apply the
parking brake fully when exiting the vehicle
to guard against vehicle movement and
possible injury or damage.
Your vehicle could move and injure you and
others if it is not in PARK. Check by trying to
move the transmission gear selector out of
PARK with the brake pedal released. Make
sure the transmission is in PARK before
exiting the vehicle.
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 indicator solidly indicates PARK (P)
without blinking. Ensure that the vehicle is
completely stopped, and the PARK position
is properly indicated, before exiting the
vehicle.
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 accel -
erate 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.
WARNING! (Continued)
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, and turn the igni -
tion OFF. When the ignition is in the OFF
mode, the transmission is locked in PARK,
securing the vehicle against unwanted
movement.
When exiting the vehicle, always make sure
the ignition 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 transmission gear
selector.
WARNING! (Continued)
4

21_DT_OM_EN_USC_t.book Page 157

STARTING AND OPERATING173
AXLE LOCK SYSTEM — IF EQUIPPED
This vehicle is equipped with an electronically
locking rear differential. When engaged, this
differential locks the axle shafts forcing the
wheels to spin at an equal rate. The locking of
the rear differential should only be engaged
during low-speed, extreme off-road situations
where one wheel is likely to not be in contact
with the ground. It is not recommended to drive
the vehicle with the differentials locked on
pavement due to the reduced ability to turn and
speed limitations.

Axle Lock Button
The locking rear axle is controlled by the AXLE
LOCK button.
Under normal driving conditions, the rear axle
should be unlocked.
During the command to lock the rear axle, the
indicator light will flash until the axle is locked.
After the lock command has been successfully
executed, the light will remain on solid.
Operating in 4WD LOW the locker can be
engaged up to 40 mph (64 km/h) and will
remain engaged throughout the 4WD LOW
speed range. Operating the locker in 2WD, 4WD AUTO, and
4WD LOCK/HIGH, the locker can be engaged up
to 20 mph (32 km/h). While driving with the
locker engaged, if speed exceeds 25 mph
(40 km/h), the locker will automatically
disengage, but will automatically reengage at
20 mph (32 km/h).
NOTE:
Left to right wheel speed difference may be
necessary to allow the rear axle to fully lock. If
the indicator light is flashing after selecting the
rear axle lock mode, drive the vehicle in a turn
or on loose gravel to expedite the locking action.
The axle locker could become torque locked
due to side to side loads on the rear axle.
Driving slowly while turning the steering wheel
from a left hand turn to a right hand turn or
driving in REVERSE for a short distance may be
required to release the torque lock and unlock
the axles.
To unlock the rear axle; push the AXLE LOCK
button. The AXLE LOCK indicator light will go out
when the rear axle is unlocked.
CAUTION!
Do not lock the rear axle on hard surfaced
roads. The ability to steer the vehicle is
reduced and damage to the drivetrain may
occur when the axle is locked on hard
surfaced roads.
Do not try to lock the rear axle if the vehicle
is stuck and the tires are spinning. You can
damage drivetrain components. Lock the
rear axle before attempting situations or
navigating terrain, which could possibly
cause the vehicle to become stuck.
4

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174STARTING AND OPERATING
LIMITED-SLIP DIFFERENTIAL — IF
EQUIPPED
The limited-slip differential provides additional
traction on snow, ice, mud, sand and gravel,
particularly when there is a difference between
the traction characteristics of the surface under
the right and left rear wheels. During normal
driving and cornering, the limited-slip unit
performs similarly to a conventional differential.
On slippery surfaces, however, the differential
delivers more of the driving effort to the rear
wheel having the better traction.
The limited-slip differential is especially helpful
during slippery driving conditions. With both
rear wheels on a slippery surface, a slight
application of the accelerator will supply
maximum traction. When starting with only one
rear wheel on an excessively slippery surface,
slight momentary application of the parking
brake may be necessary to gain maximum
traction. Care should be taken to avoid sudden
accelerations when both rear wheels are on a
slippery surface. This could cause both rear
wheels to spin, and allow the vehicle to slide
sideways on the crowned surface of a road or in
a turn.
POWER STEERING
ELECTRIC POWER STEERING
The electric power steering system will provide
increased vehicle response and ease of
maneuverability. The power steering system
adapts to different driving conditions.
If the steering icon is flashing, it indicates that
the vehicle needs to be taken to the dealer for
service. It is likely the vehicle has lost power
steering assistance.If the steering icon is displayed and the “POWER
STEERING SYSTEM OVER TEMP” message is
displayed on the instrument cluster screen, this
indicates an over temperature condition in the
power steering system. Once driving conditions
are safe, pull over and let the vehicle idle for a
few moments until the icon and message turn
off Ú
page 114.
If the steering icon is displayed and the
“SERVICE POWER STEERING – ASSIST OFF”
message is displayed the instrument cluster
screen, this indicates the vehicle needs to be
taken to the dealer for service Ú page 114.
NOTE:
Even if the power steering assistance is no
longer operational, it is still possible to steer
the vehicle. Under these conditions there will
be a substantial increase in steering effort,
especially at low speeds and during parking
maneuvers.
If the condition persists, see an authorized
dealer for service.
WARNING!
When servicing vehicles equipped with a
limited-slip or locking differential never run
the engine with one rear wheel off the ground
since the vehicle may drive through the rear
wheel remaining on the ground and result in
unintended movement.

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182STARTING AND OPERATING
To Set A Desired ACC Speed
When the vehicle reaches the speed desired,
push the SET (+) button or the SET (-) button
and release. The instrument cluster display will
show the set speed.
NOTE:
Fixed Speed Cruise Control can be used without
an ACC distance set. To change between the
different modes, push the ACC on/off button
which turns the ACC and the Fixed Speed Cruise
Control off. Pushing the Fixed Speed Cruise
Control on/off button will result in turning on
(changing to) Fixed Speed Cruise Control mode. If ACC is set when the vehicle speed is
below
20 mph (32 km/h), the set speed will default to
20 mph (20 km/h).
NOTE:
Fixed Speed Cruise Control cannot be set below
20 mph (32 km/h).
If either system is set when the vehicle speed is
above 20 mph (32 km/h), the set speed shall
be the current speed of the vehicle.
NOTE:
Keeping your foot on the accelerator pedal
can cause the vehicle to continue to accel -
erate beyond the set speed. If this occurs, the
message “ACC DRIVER OVERRIDE” will
display in the instrument cluster display.
If you continue to accelerate beyond the set
speed while an ACC distance is also set, the
system will not be controlling the distance
between your vehicle and the vehicle ahead.
The vehicle speed will only be determined by
the position of the accelerator pedal.
To Cancel
The following conditions cancel the ACC or Fixed
Speed Cruise Control systems:
The brake pedal is applied
The CANC (cancel) button is pushed
The Anti-Lock Brake system (ABS) activates
The trailer brake is applied manually (if
equipped)
The gear selector is removed from the DRIVE
position
The Electronic Stability Control/Traction
Control System (ESC/TCS) activates
The vehicle parking brake is applied
The Trailer Sway Control (TSC) activates
The driver switches ESC to Full Off mode
The braking temperature exceeds normal
range (overheated)
The following conditions will only cancel the ACC
system:
Driver seat belt is unbuckled at low speeds
Driver door is opened at low speeds
WARNING!
In the Fixed Speed Cruise Control mode, the
system will not react to vehicles ahead. In
addition, the proximity warning does not
activate and no alarm will sound even if you
are too close to the vehicle ahead since
neither the presence of the vehicle ahead nor
the vehicle-to-vehicle distance is detected. Be
sure to maintain a safe distance between
your vehicle and the vehicle ahead. Always be
aware which mode is selected.

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186STARTING AND OPERATING
and snow, or tunnels with reflective tiles). The
ACC system will recover after the vehicle has left
these areas. Under rare conditions, when the
radar is not tracking any vehicles or objects in
its path this warning may temporarily occur.
NOTE:
If the “ACC/FCW Unavailable Wipe Front Radar
Sensor” warning is active, Fixed Speed Cruise
Control is still available.
If weather conditions are not a factor, the driver
should examine the sensor. It may require
cleaning or removal of an obstruction. The
sensor is located in the camera in the center of
the windshield, on the forward side of the
rearview mirror.
To keep the ACC system operating properly, it is
important to note the following maintenance
items:
Always keep the sensor clean. Carefully clear
the windshield.
Do not remove any screws from the sensor.
Doing so could cause an ACC system
malfunction or failure and require a sensor
realignment.
Do not attach or install any accessories near
the sensor, including transparent material.
Doing so could cause an ACC system failure
or malfunction.
When the condition that deactivated the system
is no longer present, the system will return to
the “Adaptive Cruise Control Off” state and will
resume function by simply reactivating it.
NOTE:
If the “ACC/FCW Unavailable Wipe Front
Radar Sensor” message occurs frequently
(e.g. more than once on every trip) without
any snow, rain, mud, or other obstruction,
have the radar sensor realigned at an autho -
rized dealer.
Installing a snow plow, front-end protector,
an aftermarket grille or modifying the grille is
not recommended. Doing so may block the
sensor and inhibit ACC/FCW operation. “Clean Front Windshield” Warning
The “ACC/FCW Limited Functionality Clean
Front Windshield” warning will display and also
a chime will indicate when conditions
temporarily limit system performance. This
most often occurs at times of poor visibility,
such as in snow or heavy rain and fog. The ACC
system may also become temporarily blinded
due to obstructions, such as mud, dirt, or ice on
windshield, driving directly into the sun and fog
on the inside of glass. In these cases, the
instrument cluster display will show “ACC/FCW
Limited Functionality Clean Front Windshield”
and the system will have degraded
performance.
This message can sometimes be displayed
while driving in adverse weather conditions. The
ACC/FCW system will recover after the vehicle
has left these areas. Under rare conditions,
when the camera is not tracking any vehicles or
objects in its path this warning may temporarily
occur.

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