engine RAM 1500 2021 Repair Manual

STARTING AND OPERATING159
During extremely cold temperatures (-22°F
[-30°C] or below), transmission operation may
be modified depending on engine and
transmission temperature as well as vehicle
speed. Normal operation will resume once the
transmission temperature has risen to a
suitable level.
Transmission Limp Home Mode
Transmission function is monitored
electronically for abnormal conditions. If a
condition is detected that could result in
transmission damage, Transmission Limp
Home Mode is activated. In this mode, the
transmission may operate only in certain gears,
or may not shift at all. Vehicle performance may
be severely degraded and the engine may stall.
In some situations, the transmission may not
re-engage if the engine is turned off and
restarted. The Malfunction Indicator Light (MIL)
may be illuminated. A message in the
instrument cluster will inform the driver of the
more serious conditions, and indicate what
actions may be necessary. In the event of a momentary problem, the
transmission can be reset to regain all forward
gears by performing the following steps:
NOTE:
In cases where the instrument cluster message
indicates the transmission may not re-engage
after engine shutdown, perform this procedure
only in a desired location (preferably, at an
authorized dealer).

1. Stop the vehicle.

2. Shift the transmission into PARK, if
possible. If not, shift the transmission to
NEUTRAL.
3. Push and hold the ignition switch until the engine turns off.
4. Wait approximately 30 seconds.
5. Restart the engine.
6. Shift into the desired gear range. If the problem is no longer detected, the
transmission will return to normal
operation. NOTE:
Even if the transmission can be reset, we
recommend that you visit an authorized dealer
at your earliest possible convenience. An autho
-
rized dealer has diagnostic equipment to
assess the condition of your transmission. If the
transmission cannot be reset, an authorized
dealer service is required.Electronic Range Select (ERS) Operation
The Electronic Range Select (ERS) shift control
allows the driver to limit the highest available
gear when the transmission is in DRIVE and ERS
mode is not active. For example, if you set the
transmission gear limit to FOURTH gear, the
transmission will not shift above FOURTH gear
(except to prevent engine overspeed), but will
shift through the lower gears normally.
You can switch between DRIVE and ERS mode
at any vehicle speed. When the transmission
gear selector is in DRIVE, the transmission will
operate automatically, shifting between all
available gears. Tapping the - button (on the
steering wheel) 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 the - or + button will change
the top available gear.4

21_DT_OM_EN_USC_t.book Page 159

160STARTING AND OPERATING

Electronic Range Select (ERS)

To exit ERS mode, simply push and hold the +
button until the gear limit display disappears
from the instrument cluster.
When to Use TOW/HAUL Mode
Select TOW/HAUL mode when driving in
conditions such as: driving in hilly areas, towing
a trailer, carrying a heavy load, etc. This mode
will improve performance and reduce the
potential for transmission overheating or failure
due to excessive shifting.

TOW/HAUL Switch
The “TOW/HAUL Indicator Light” will illuminate
in the instrument cluster to indicate that TOW/
HAUL mode has been activated. Pushing the
switch a second time restores normal
operation. Normal operation is always the
default at engine start-up. If TOW/HAUL mode is
desired, the switch must be pushed each time
the engine is started.
1 — Shift Up (+)
2 — Shift Down (–)
WARNING!
Do not downshift for additional engine brak
-
ing on a slippery surface. The drive wheels
could lose their grip and the vehicle could
skid, causing a collision or personal injury.
WARNING!
Do not use the “TOW/HAUL” feature when
driving in icy or slippery conditions. The
increased engine braking can cause the rear
wheels to slide, and the vehicle to swing
around with the possible loss of vehicle con -
trol, which may cause an accident possibly
resulting in personal injury or death.

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162STARTING AND OPERATING
NOTE:
The 4WD High and 4WD Low positions are
designed for loose, slippery road surfaces
only. Driving in the 4WD High and 4WD Low
positions on dry, hard surfaced roads may
cause increased tire wear and damage to the
driveline components.
The transfer case N (Neutral) button is located
in the center of the 4WD Control Switch and is
pushed by using a ballpoint pen or similar
object. The transfer case N (Neutral) position
is to be used for recreational towing only
Úpage 231.
Transfer Case Position Indicator Lights
The Transfer Case Position Indicator Lights
(4WD High and 4WD Low) are located in the
instrument cluster and indicate the current and
desired transfer case selection. When you
select a different transfer case position, the
indicator lights will do the following:

1. The current position indicator light will turn off.

2. The selected position indicator light will flash until the transfer case completes the
shift. 3. When the shift is complete, the indicator
light for the selected position will stop
flashing and remain on.
If the transfer case does not shift into the
desired position, one or more of the following
events may occur:

1. The indicator light for the current position will remain on.

2. The newly selected position indicator light will continue to flash.
3. If the transfer case will not shift, a message
will appear on the cluster stating the 4WD
shift has canceled.
NOTE:
Before retrying a selection, make certain that all
the necessary requirements for selecting a new
transfer case position have been met. To retry
the selection, push the current position, wait
five seconds, and retry selection.
The “SVC 4WD Warning Light” monitors the
electronic shift four-wheel drive system. If this
light remains on after engine start up or
illuminates during driving, it means that the
four-wheel drive system is not functioning
properly and that service is required. NOTE:
Do not attempt to make a shift while only the
front or rear wheels are spinning. This could
cause damage to driveline components.
When operating your vehicle in 4WD Low, the
engine speed is approximately three times that
of the 2WD or 4WD High positions at a given
road speed. Take care not to overspeed the
engine and do not exceed 25 mph (40 km/h).
Proper operation of four-wheel drive vehicles
depends on tires of equal size, type and
circumference on each wheel. Any difference in
tire size can cause damage to the drivetrain.
Because four-wheel drive provides improved
traction, there is a tendency to exceed safe
turning and stopping speeds. Do not go faster
than road conditions permit.
WARNING!
Always engage the parking brake when
powering down the vehicle if the “SVC 4WD
Warning Light” is illuminated. Not engaging
the parking brake may allow the vehicle to roll
which may cause personal injury or death.

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164STARTING AND OPERATING
NOTE:
The 4WD High and 4WD Low positions are
designed for loose, slippery road surfaces
only. Driving in the 4WD High and 4WD Low positions on dry hard surfaced roads may
cause increased tire wear and damage to the
driveline components.
The transfer case N (Neutral) button is
located in the center of the 4WD Control
Switch and is pushed by using a ballpoint pen
or similar object. The transfer case N
(Neutral) position is to be used for recre
-
ational towing only Ú page 231.
Transfer Case Position Indicator Lights
The Transfer Case Position Indicator Lights
(4WD High, 4WD Low, and 4WD Auto) are
located in the instrument cluster and indicate
the current and desired transfer case selection.
When you select a different transfer case
position, the indicator lights will do the
following:

1. The current position indicator light will turn off.

2. The selected position indicator light will flash until the transfer case completes the
shift.
3. When the shift is complete, the indicator light for the selected position will stop
flashing and remain on. If the transfer case does not shift into the
desired position, one or more of the following
events may occur:

1. The indicator light for the current position
will remain on.

2. The newly selected position indicator light will continue to flash.
3. If the transfer case will not shift, there will
be a cluster message stating the 4WD shift
has canceled.
NOTE:
Before retrying a selection, make certain that all
the necessary requirements for selecting a new
transfer case position have been met. To retry
the selection, push the current position, wait
five seconds, and retry selection.
The “SVC 4WD Warning Light” monitors the
electronic shift four-wheel drive system. If this
light remains on after engine start up or
illuminates during driving, it means that the
four-wheel drive system is not functioning
properly and that service is required.
WARNING!
You or others could be injured or killed if
you leave the vehicle unattended with the
transfer case in the N (Neutral) position
without first fully engaging the parking
brake. The transfer case N (Neutral) posi -
tion disengages both the front and rear
drive shaft from the powertrain, and will
allow the vehicle to roll, even if the trans -
mission is in PARK. The parking brake
should always be applied when the driver is
not in 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.

21_DT_OM_EN_USC_t.book Page 164

STARTING AND OPERATING165
NOTE:
Do not attempt to make a shift while only the
front or rear wheels are spinning. This could
cause damage to driveline components.
When operating your vehicle in 4WD Low, the
engine speed is approximately three times that
of the 2WD, 4WD Auto or 4WD High positions
at a given road speed. Take care not to
overspeed the engine and do not exceed
25 mph (40 km/h).
Proper operation of four-wheel drive vehicles
depends on tires of equal size, type and
circumference on each wheel. Any difference in
tire size can cause damage to the drivetrain.
Because four-wheel drive provides improved
traction, there is a tendency to exceed safe
turning and stopping speeds. Do not go faster
than road conditions permit.
Shifting Procedure
If any of the requirements to select a new
transfer case position have not been met,
then the transfer case will not shift. The posi -
tion indicator light for the previous position
will remain on and the newly selected posi -
tion indicator light will continue to flash until
all the requirements for the selected position
have been met.
If all the requirements to select a new
transfer case position have been met, then
the current position indicator light will turn off
and the selected position indicator light will
flash until the transfer case completes the
shift. When the shift is complete, the position
indicator light for the selected position will
stop flashing and remain on.
ACTIVE-LEVEL FOUR CORNER AIR
SUSPENSION SYSTEM — IF EQUIPPED
DESCRIPTION
The air suspension system provides full time
load leveling capability along with the benefit of
being able to adjust vehicle height by using the
toggle switch.
Air Suspension Switch

Normal Ride Height (NRH)
– This is the stan-
dard position of the suspension and is meant
for normal driving.

Off-Road 1 (OR1) (Raises the vehicle
approximately 1 inch (26 mm)) – This posi-
tion should be the primary position for all
off-road driving until Off-Road 2 (OR2) is
needed. A smoother and more comfortable
ride will result. To enter OR1, push the

WARNING!
Always engage the parking brake when
powering down the vehicle if the “SVC 4WD
Warning Light” is illuminated. Not engaging
the parking brake may allow the vehicle to roll
which may cause personal injury or death.
1 — Off-Road 2 Indicator (Customer Selectable)
2 — Off-Road 1 Indicator (Customer Selectable)
3 — Normal Ride Height Indicator (Customer Se -
lectable)
4 — Aero Mode Indicator (Customer Selectable)
5 — Entry/Exit Mode Indicator (Customer Select -
able)
4

21_DT_OM_EN_USC_t.book Page 165

STARTING AND OPERATING167
to Normal Height Mode, push the height
selector switch up once while in Entry/Exit or
drive the vehicle over 15 mph (24 km/h).
Entry/Exit mode may not be available due to
vehicle payload, an instrument cluster
message will be displayed when this occurs
Úpage 114.
NOTE:
Entry/Exit mode may be achieved using your
key fob for easier entry/loading Ú page 17.
The system requires that the ignition be in the
ON/RUN position or the engine running for all
user requested changes. When lowering the
vehicle, all of the doors must be closed. If a door
is opened at any time while the vehicle is
lowering, the change will not be completed until
the open door(s) is closed. This system uses a lifting and lowering pattern
which keeps the headlights from incorrectly
shining into oncoming traffic. When raising the
vehicle, the rear of the vehicle will move up first
and then the front. When lowering the vehicle,
the front will move down first and then the rear.
After the engine is turned off, it may be noticed
that the air suspension system operates briefly;
this is normal. The system is correcting the
position of the vehicle to ensure a proper
appearance.
To assist with changing a spare tire, the air
suspension system has a feature which allows
the automatic leveling to be disabled
Ú
page 114.
NOTE:
If equipped with a touchscreen radio, all
enabling/disabling of air suspension features
must be done through the radio Ú page 237.AIR SUSPENSION MODES
The air suspension system has multiple modes
to protect the system in unique situations. The
engine should be running to change between
Air Suspension Modes.
Automatic AERO Mode
To improve aerodynamics, the air suspension
system has a feature which will put the vehicle
into AERO height automatically Úpage 114.
Automatic Aero Mode may be disabled through
vehicle settings in the Uconnect Radio (if
equipped) Ú page 237.
Tire Jack Mode
To assist with changing a tire, the air
suspension system has a feature which allows
the automatic leveling to be disabled
Ú page 237.
Transport Mode
For towing your vehicle with four wheels off the
road, the air suspension system has a feature
which will put the vehicle into Entry/Exit height
and disable the automatic load leveling system
Ú page 237.
CAUTION!
When in ENTRY/EXIT setting, be aware of your
surroundings, you may not have the
clearance required for certain areas and
vehicle damage may occur.
WARNING!
The air suspension system uses a high
pressure volume of air to operate the system.
To avoid personal injury or damage to the
system, see an authorized dealer for service.
4

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168STARTING AND OPERATING
Wheel Alignment Mode
Before performing a wheel alignment, this
mode must be enabled Úpage 237.
Protection Strategy
In order to “protect” the air suspension system,
the vehicle will disable load leveling as required
(suspension overloaded, battery charge low,
etc.). Load leveling will automatically resume as
soon as system operation requirements are
met. See an authorized dealer if system does
not resume.
NOTE:
For towing with air suspension Ú page 214.
INSTRUMENT CLUSTER DISPLAY
M
ESSAGES
When the appropriate conditions exist, a
message will appear in the instrument cluster
display Ú page 114.
An audible chime will be heard whenever a
system error has been detected.
See an authorized dealer for system service if
normal operation does not resume.
OPERATION

Air Suspension Switch

The indicator lamps 1 through 5 will illuminate
to show the current position of the vehicle.
Flashing indicator lamps will show a position
which the system is working to achieve. When
raising, if multiple indicator lamps are flashing,
the highest flashing indicator lamp is the
position the system is working to achieve. When
lowering, if multiple indicators are flashing, the
lowest solid indicator lamp is the position the
system is working to achieve.
Pushing the height selector up once will move
the suspension one position higher from the
current position, assuming all conditions are
met (i.e. key in ON/RUN position, engine
running, speed below threshold, etc). The height selector switch can be pushed up
multiple times, each push will raise the
requested level by one position up to a
maximum position of OR2 or the highest
position allowed based on current conditions
(i.e. vehicle speed, etc).
Pushing the height selector down once will
move the suspension one position lower from
the current level, assuming all conditions are
met (i.e. key in ON/RUN position, engine
running, doors closed, speed below threshold,
etc). The height selector switch can be pushed
down multiple times, each push will lower the
requested level by one position down to a
minimum of Entry/Exit Mode or the lowest
position allowed based on current conditions
(i.e. vehicle speed, etc.)
Automatic height changes will occur based on
vehicle speed and the current vehicle height.
The indicator lamps and instrument cluster
display messages will operate the same for
automatic changes and user requested
changes.

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170STARTING AND OPERATING
OR, if the vehicle speed exceeds 25 mph
(40 km/h) the vehicle height will be automat -
ically lowered to NRH. Off-Road may not be
available due to vehicle payload, an instru -
ment cluster display message will be shown
when this occurs Ú page 114.

Aero Mode (Lowers the vehicle approxi -
mately 0.6 inches (15 mm)) – This position
provides improved aerodynamics by
lowering the vehicle. The vehicle will auto -
matically enter Aero Mode when the vehicle
speed remains between 62 mph (100 km/h)
and 66 mph (106 km/h) for greater than 20 seconds or if the vehicle speed exceeds
66 mph (106 km/h). The vehicle will return to NRH from Aero Mode if the vehicle speed
remains between 30 mph (48 km/h) and
35 mph (56 km/h) for greater than 20 seconds or if the vehicle speed falls
below 30 mph (48 km/h).
NOTE:
The vehicle will automatically enter Aero
Mode when the vehicle speed remains
between 62 mph (100 km/h) and 66 mph
(106 km/h) for greater than
20 seconds or if the vehicle speed exceeds
66 mph (106 km/h).
Speed thresholds for raising the vehicle only
apply if Automatic Aero Mode is enabled.
To enter Aero Mode manually push the height
selector switch down once from NRH at any
vehicle speed. To return to NRH push the
height selector switch up once while vehicle
speed is less than 56 mph (90 km/h).
Automatic Aero Mode may be disabled
through vehicle settings on your Uconnect
Radio.
Entry/Exit Mode (Lowers the vehicle approxi-
mately 3 inches (73 mm))
– This position
lowers the vehicle for easier passenger entry
and exit as well as lowering the rear of the
vehicle for easier loading and unloading of
cargo. To enter Entry/Exit Mode, push the
height selector switch down twice from the
NRH while the vehicle speed is below 33 mph
(53 km/h). Once the vehicle speed goes below 15 mph (24 km/h) the vehicle height
will begin to lower. If the vehicle speed
remains between 15 mph (24 km/h) and
25 mph (40 km/h) for greater than
60 seconds, or the vehicle speed exceeds
25 mph (40 km/h) the Entry/Exit change will
be canceled. To return to Normal Height
Mode, push the height selector switch up
twice while in Entry/Exit or drive the vehicle
over 15 mph (24 km/h). Entry/Exit mode
may not be available due to vehicle payload,
an instrument cluster display message will
be shown when this occurs Ú
page 114.
The system requires that the ignition be in the
ON/RUN position or the engine running for all
user requested changes. When lowering the
vehicle, all of the doors must be closed. If a door
is opened at any time while the vehicle is
lowering, the change will not be completed until
the open door(s) is closed.
CAUTION!
If the vehicle is in Off-Road setting, be aware
of your surroundings, you may not have the
clearance required for certain areas and
vehicle damage may occur.
CAUTION!
When in ENTRY/EXIT setting, be aware of your
surroundings, you may not have the
clearance required for certain areas and
vehicle damage may occur.

21_DT_OM_EN_USC_t.book Page 170

STARTING AND OPERATING171
This system uses a lifting and lowering pattern
which keeps the headlights from incorrectly
shining into oncoming traffic. When raising the
vehicle, the rear of the vehicle will move up first
and then the front. When lowering the vehicle,
the front will move down first and then the rear.
After the engine is turned off, it may be noticed
that the air suspension system operates briefly;
this is normal. The system is correcting the
position of the vehicle to ensure a proper
appearance.
To assist with changing a spare tire, the air
suspension system has a feature which allows
the automatic leveling to be disabled
Úpage 237.
NOTE:
If equipped with a touchscreen radio, all
enabling/disabling of air suspension features
must be done through the radio Ú page 237.AIR SUSPENSION MODES
The Air Suspension system has multiple modes
to protect the system in unique situations:
AERO Mode
To improve aerodynamics, the air suspension
system has a feature which will put the vehicle
into AERO height automatically Úpage 114.
Tire Jack Mode
To assist with changing a tire, the air
suspension system has a feature which allows
the automatic leveling to be disabled
Ú page 237.
Transport Mode
For towing your vehicle with four wheels off the
road, the air suspension system has a feature
which will put the vehicle into Entry/Exit height
and disable the automatic load leveling system
Ú page 237.
Wheel Alignment Mode
Before performing a wheel alignment, this
mode must be enabled Ú page 237.Protection Strategy
In order to “protect” the air suspension system,
the vehicle will disable load leveling as required
(suspension overloaded, battery charge low,
etc.). Load leveling will automatically resume as
soon as system operation requirements are
met. See an authorized dealer if system does
not resume.
NOTE:
For towing with air suspension Ú
page 214.
INSTRUMENT CLUSTER DISPLAY
M
ESSAGES
When the appropriate conditions exist, a
message will appear in the instrument cluster
display Ú page 114.
An audible chime will be heard whenever a
system error has been detected.
See an authorized dealer for system service if
normal operation does not resume.
WARNING!
The air suspension system uses a high
pressure volume of air to operate the system.
To avoid personal injury or damage to the
system, see an authorized dealer for service.
4

21_DT_OM_EN_USC_t.book Page 171

172STARTING AND OPERATING
OPERATION

Air Suspension Switch

The indicator lamps 1 through 4 will illuminate
to show the current position of the vehicle.
Flashing indicator lamps will show a position
which the system is working to achieve. When
raising or lowering, the flashing indicator lamp
is the position the system is working to achieve.
Pushing the height selector switch up once will
move the suspension one position higher from
the current position, assuming all conditions
are met (i.e. key in ON/RUN position, engine
running, speed below threshold, etc). The
height selector switch can be pushed up
multiple times, each push will raise the
requested level by one position up to a maximum position of OR or the highest position
allowed based on current conditions (i.e.
vehicle speed, etc).
Pushing the height selector switch down once
will move the suspension one position lower
from the current level, assuming all conditions
are met (i.e. key in ON/RUN position, engine
running, doors closed, speed below threshold,
etc). The height selector switch can be pushed
down multiple times, each push will lower the
requested level by one position down to a
minimum of Entry/Exit Mode or the lowest
position allowed based on current conditions
(i.e. vehicle speed, etc.)
Automatic height changes will occur based on
vehicle speed and the current vehicle height.
The indicator lamps and instrument cluster
display messages will operate the same for
automatic changes and user requested
changes.
Off-Road 1 (OR1) – Indicator lamps 4, 3, 2,
and 1 will be illuminated when the vehicle is
in OR1.
Normal Ride Height (NRH) – Indicator lamps
4, 3, and 2 will be illuminated when the
vehicle is in this position.
Aero Mode – Indicator lamps 4 and 3 will be
illuminated when the vehicle is in this posi
-
tion.

Entry/Exit Mode – Indicator lamp 4 will be
illuminated when the vehicle is in Entry Exit
Mode. Entry/Exit mode can be requested up
to 33 mph (53 km/h). If vehicle speed is reduced to, and kept below, 15 mph
(24 km/h) indicator lamp 3 will flash and
indicator lamp 4 will remain solid until
Entry/Exit Mode is achieved at which point
indicator lamp 3 will turn off.

Transport Mode – No indicator lamps will be
illuminated. Transport Mode is disabled by
driving the vehicle.
Tire/Jack Mode – Indicator lamps 4 and 1 will
be illuminated. Tire/Jack Mode is disabled by
driving the vehicle.
Wheel Alignment Mode – Indicator lamps 2,
3, and 4 will be illuminated. Wheel Alignment
Mode is disabled by driving the vehicle.

21_DT_OM_EN_USC_t.book Page 172