2019 Ram 1500 ECU

The locking rear axle is controlled by the AXLE LOCKER
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 neces-
sary 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.
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 simi-
larly 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
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STARTING AND OPERATING 335

The engine will shut down, the tachometer will move to
the zero position and the stop/start telltale will illuminate
indicating you are in an Autostop. While in an Autostop,
the Climate Controls system may automatically adjust
airflow to maintain cabin comfort. Customer settings will
be maintained upon return to an engine running condition.
Possible Reasons The Engine Does Not Autostop
Prior to engine shut down, the system will check many
safety and comfort conditions to see if they are fulfilled. In
following situations, the engine will not Autostop:
•Driver ’s seat belt is not buckled.
• Driver ’s door is not closed.
• The vehicle is on a steep grade.
• Cabin heating or cooling is in process and an acceptable
cabin temperature has not been achieved.
• HVAC is set to full defrost mode at a high blower speed.
• Engine has not reached normal operating temperature.
• Engine temperature too high.
• The battery is charging.
• The transmission is not in DRIVE. •
Hood is open.
• Vehicle is in 4LO transfer case mode.
• Accelerator pedal input.
• Excessive 12 volt loads.
It may be possible to operate the vehicle several consecu-
tive times in extreme conditions and not meet all criteria to
enable an Autostop state.
To Start The Engine While In Autostop Mode
While in DRIVE, the engine will start when the brake pedal
is released or the throttle pedal is depressed and the
transmission will automatically reengage upon engine
restart.
Conditions That Will Cause The Engine To Start Auto-
matically While In Autostop Mode
The engine will start automatically when:
• The transmission selector is moved from DRIVE to
REVERSE, NEUTRAL, or PARK.
• To maintain cabin temperature near the HVAC settings.
• HVAC is set to full defrost mode.
• 12 volt demand requires engine restart.
338 STARTING AND OPERATING

ACC Operation At Stop
In the event that the ACC system brings your vehicle to a
standstill while following a target vehicle, if the target
vehicle starts moving within two seconds of your vehicle
coming to a standstill, your vehicle will resume motion
without the need for any driver action.
If the target vehicle does not start moving within two
seconds of your vehicle coming to a standstill, the driver
will either have to push the RES (resume) button, or apply
the accelerator pedal to reengage the ACC to the existing
Set Speed.
NOTE:After the ACC system holds your vehicle at a
standstill for approximately 3 consecutive minutes, the
parking brake will be activated, and the ACC system will
be cancelled.
While ACC is holding your vehicle at a standstill, if the
driver seatbelt is unbuckled or the driver door is opened,
the parking brake will be activated, and the ACC system
will be cancelled.
WARNING!
When the ACC system is resumed, the driver must
ensure that there are no pedestrians, vehicles or objects
in the path of the vehicle. Failure to follow these
warnings can result in a collision and death or serious
personal injury.
Adaptive Cruise Control (ACC) Menu
The instrument cluster display will show the current ACC
system settings. The instrument cluster display is located
in the center of the instrument cluster. The information it
displays depends on ACC system status.
Push the Adaptive Cruise Control (ACC) on/off button
(located on the steering wheel) until one of the following
appears in the instrument cluster display:
Adaptive Cruise Control Off
When ACC is deactivated, the display will read “Adaptive
Cruise Control Off.”
354 STARTING AND OPERATING

Curb Weight
The curb weight of a vehicle is defined as the total weight
of the vehicle with all fluids, including vehicle fuel, at full
capacity conditions, and with no occupants or cargo loaded
into the vehicle. The front and rear curb weight values are
determined by weighing your vehicle on a commercial
scale before any occupants or cargo are added.
Loading
The actual total weight and the weight of the front and rear
of your vehicle at the ground can best be determined by
weighing it when it is loaded and ready for operation.
The entire vehicle should first be weighed on a commercial
scale to insure that the GVWR has not been exceeded. The
weight on the front and rear of the vehicle should then be
determined separately to be sure that the load is properly
distributed over the front and rear axle. Weighing the
vehicle may show that the GAWR of either the front or rear
axles has been exceeded but the total load is within the
specified GVWR. If so, weight must be shifted from front to
rear or rear to front as appropriate until the specified
weight limitations are met. Store the heavier items down
low and be sure that the weight is distributed equally. Stow
all loose items securely before driving.Improper weight distributions can have an adverse effect
on the way your vehicle steers and handles and the way
the brakes operate.
CAUTION!
Do not load your vehicle any heavier than the GVWR
or the maximum front and rear GAWR. If you do, parts
on your vehicle can break, or it can change the way
your vehicle handles. This could cause you to lose
control. Also overloading can shorten the life of your
vehicle.
TRAILER TOWING
In this section you will find safety tips and information on
limits to the type of towing you can reasonably do with
your vehicle. Before towing a trailer, carefully review this
information to tow your load as efficiently and safely as
possible.
To maintain the New Vehicle Limited Warranty coverage,
follow the requirements and recommendations in this
manual concerning vehicles used for trailer towing.
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STARTING AND OPERATING 407

CAUTION!(Continued)
•Then, during the first 500 miles (805 km) that a trailer
is towed, do not drive over 50 mph (80 km/h) and do
not make starts at full throttle. This helps the engine
and other parts of the vehicle wear in at the heavier
loads.
Perform the maintenance listed in the “Scheduled Servic-
ing”. Refer to “Scheduled Servicing” in “Servicing And
Maintenance” for the proper maintenance intervals. When
towing a trailer, never exceed the GAWR or GCWR ratings.
WARNING!
Improper towing can lead to a collision. Follow these
guidelines to make your trailer towing as safe as
possible:
• Make certain that the load is secured in the trailer
and will not shift during travel. When trailering
cargo that is not fully secured, dynamic load shifts
can occur that may be difficult for the driver to
control. You could lose control of your vehicle and
have a collision.
(Continued)
WARNING! (Continued)
•When hauling cargo or towing a trailer, do not
overload your vehicle or trailer. Overloading can
cause a loss of control, poor performance or damage
to brakes, axle, engine, transmission, steering, sus-
pension, chassis structure or tires.
• Safety chains must always be used between your
vehicle and trailer. Always connect the chains to the
hook retainers of the vehicle hitch. Cross the chains
under the trailer tongue and allow enough slack for
turning corners.
• Vehicles with trailers should not be parked on a
grade. When parking, apply the parking brake on the
tow vehicle. Put the tow vehicle transmission in
PARK. For four-wheel drive vehicles, make sure the
transfer case is not in NEUTRAL. Always, block or
chock the trailer wheels.
• GCWR must not be exceeded.
(Continued)
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STARTING AND OPERATING 415

Recreational Towing — Two-Wheel Drive Models
DO NOT flat tow this vehicle. Damage to the drivetrain
will result.
Recreational towing (for two-wheel drive models) is al-
lowedONLY if the rear wheels are OFFthe ground. This
may be accomplished using a tow dolly or vehicle trailer. If
using a tow dolly, follow this procedure:
NOTE: If vehicle is equipped with air suspension, ensure
the vehicle is set to Normal Ride Height.
1. Properly secure the dolly to the tow vehicle, following the dolly manufacturer’s instructions.
2. Drive the rear wheels onto the tow dolly.
3. Apply the parking brake. Place the transmission in PARK.
4. Properly secure the rear wheels to the dolly, following the dolly manufacturer’s instructions.
5. Turn the ignition OFF.
6. Install a suitable clamping device, designed for towing, to secure the front wheels in the straight position.
CAUTION!
Towing with the rear wheels on the ground will cause
severe transmission damage. Damage from improper
towing is not covered under the New Vehicle Limited
Warranty.
Recreational Towing — Four-Wheel Drive Models
NOTE: The transfer case must be shifted into NEUTRAL
(N) for recreational towing. The transmission must be
shifted into PARK for recreational towing. Refer to the
following for the proper transfer case NEUTRAL (N)
shifting procedure for your vehicle.
CAUTION!
• DO NOT dolly tow any 4WD vehicle. Towing with
only one set of wheels on the ground (front or rear)
will cause severe transmission and/or transfer case
damage. Tow with all four wheels either ON the
ground, or OFF the ground (using a vehicle trailer).
• Tow only in the forward direction. Towing this
vehicle backwards can cause severe damage to the
transfer case.
(Continued)
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STARTING AND OPERATING 425

CavityCartridge Fuse Micro Fuse Description
F16 –– Spare
F17 –20 Amp Yellow Spare
F18 30 Amp Pink –Motor Sunshade Sunroof
F19 –– Spare
F20 –20 Amp Yellow Comfort Rear Seat Module (CRSM) (Heat
Rear RT)
F21 –– Spare
F22 –– Spare
F23 –– Spare
F24 –15 Amp Blue Mod RF Hub / Mod Ignition / Mod Cluster
F25 40 Amp Green –Mod Integrated Trailer Brake
F26 –15 Amp Blue Mod Cluster CCN / Mod Cyber Security
F27 –5 Amp Tan Mod Cluster CCN / Mod SGW
F28 –10 Amp Red Mod ORC
F29 –20 Amp Yellow Mod CRSM (Heat Rear LT)
F30 30 Amp Pink –Mod DTCM / Mod Tailgate
F31 30 Amp Pink –Mod CBC 1 Interior Light
F32 –– Spare / Sunshade
F33 –10 Amp Red Assy Overhead Console / Switch 911 /
Switch Assist / Sunshade
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IN CASE OF EMERGENCY 455

WARNING!(Continued)
•Never start or run the engine with the vehicle on a
jack.
• Do not let anyone sit in the vehicle when it is on a
jack.
• Do not get under the vehicle when it is on a jack. If
you need to get under a raised vehicle, take it to a
service center where it can be raised on a lift.
• Only use the jack in the positions indicated and for
lifting this vehicle during a tire change.
• If working on or near a roadway, be extremely
careful of motor traffic.
• To assure that spare tires, flat or inflated, are securely
stowed, spares must be stowed with the valve stem
facing the ground.
CAUTION!
Do not attempt to raise the vehicle by jacking on
locations other than those indicated in the Jacking
Instructions for this vehicle.
1. Remove the spare wheel, jack, and tools from storage.
2. Using the lug wrench, loosen, but do not remove, the wheel nuts by turning them counterclockwise one turn
while the wheel is still on the ground.
Jack Warning Label
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IN CASE OF EMERGENCY 467