2020 Ram 3500 light

226STARTING AND OPERATING
NOTE:

If ambient temperatures are low and the coolant
temperature is below 180°F (82°C), the engine
idle speed will slowly increase to 1,000 RPM after
two minutes of idle, if the following conditions are
met:

Foot is off brake pedal and throttle pedal.
Automatic transmission is in PARK.
Vehicle speed is 0 mph (0 km/h).
Applying the throttle will cancel fast idle.
Operating the exhaust brake at idle will
greatly improve warm up rate and will help
keep the engine close to operating tempera -
ture during extended idle.
ENGINE IDLING
Avoid prolonged idling, long periods of idling
may be harmful to your engine because
combustion chamber temperatures can drop so
low that the fuel may not burn completely.
Incomplete combustion allows carbon and
varnish to form on piston rings, engine valves,
and injector nozzles. Also, the unburned fuel
can enter the crankcase, diluting the oil and
causing rapid wear to the engine. If the engine is allowed to idle or the truck is
driven on low engine speed drive cycles for
more than 2 hours, the system will
automatically enter an emissions operating
mode that will increase the engine idle speed to
900 RPM. While in this mode, which is designed
to help maintain the diesel particulate filter, the
engine idle speed will return to normal when the
brake pedal is applied. A small change in engine
tone or a slight change in engine performance
while accelerating may also be noticeable at
speeds below 20 mph (32 km/h). This
operating mode may last for up to an hour of
idle time, or around 20 minutes of driving time.
Your truck may have been ordered with an
optional voltage monitoring idle up feature. If a
load is placed on the electrical system while the
truck is in park, this feature will attempt to
maintain normal system voltage by
automatically increasing engine idle speed. You
may notice several consecutive increases in
idle speed, up to a maximum of 1,450 RPM, as
the system will attempt to utilize the smallest
increase in idle speed necessary to maintain
normal system voltage. The idle speed will
return to normal when either the electrical load
is removed, or when the brake pedal is applied.
NOTE:
For instrument cluster display messages
related to the vehicle's exhaust system, refer to
“Instrument Cluster Display” in “Getting To
Know Your Instrument Panel” for further infor
-
mation.
Idle-Up Feature
The driver-controlled high idle speed feature will
help increase cylinder temperatures and
provide additional cab heat, however, excessive
idling may still cause the exhaust
aftertreatment system to not properly
regenerate. Extended periods of idle time
should be avoided.
The Idle-Up feature uses the Speed Control
switches to increase engine idle speed and
quickly warm the vehicle's interior.

1. With the transmission in PARK, the parking brake applied, and the engine running,
push the speed control switch to the ON
position, then push the SET switch.

2. The engine RPM will go up to 1,100 RPM. To increase the RPM, push and hold the
ACCEL/RESUME switch and the idle speed
will increase to approximately 1,500 RPM.
To decrease the RPM, push and hold the

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STARTING AND OPERATING227
DECEL switch and the idle speed will
decrease to approximately 1,100 RPM.
3. To cancel the Idle–Up feature, either push the CANCEL switch, push the ON/OFF
switch, or press the brake pedal.

NOISE
Diesel engines can create noises that may seem
concerning. The nature of a diesel engine is
compression ignition where compressed air and
fuel are mixed and ignited. Weather, barometric
pressure, altitude, and temperature will affect how
fuel is ignited in the engine. Engines will sound
different from day to day or previous model years.
Clicking, ticking, or light knocking is normal and will
change from day to day, as the engine breaks in, and can vary with changes in ambient
temperature. Clicking sound from under the hood
shortly after vehicle shutdown is normal as
actuators such as the EGR valve are cycled. Fuel
pump noise may increase during low speed/light
load conditions when ambient temperature is
above 100°F (38°C), and when fuel tank level is
below 10% which is a normal condition of the fuel
system and controls strategy. Diesel equipped
vehicles also have an exhaust after-treatment
system to reduce emissions utilizing a DPF (refer to
“Odor” in this section for further information) and a
Selective Reduction Catalyst (SCR). The SCR
reduces Nitrogen Oxides (NOx) using the Diesel
Exhaust Fluid (DEF) system. DEF is injected directly
into the SCR through a dosing module. This
process will create a clicking sound and at times, will make noise even with the vehicle shut off. This
is normal as the DEF dosing module is purging
DEF. If at any time the check engine light is on,
please visit an authorized dealer.

STOPPING THE ENGINE
Idle the engine a few minutes before routine
shutdown. After full load operation, idle the
engine three to five minutes before shutting it
down. This idle period will allow the lubricating
oil and coolant to carry excess heat away from
the combustion chamber, bearings, internal
components, and turbocharger. This is
especially important for turbocharged, charge
air-cooled engines. Refer to the following chart
for proper engine shutdown:
Driving Condition
Load Turbocharger Temperature Idle Time (min.) Before Engine
Shutdown
Stop and Go EmptyCoolLess than One
Stop and Go Medium -One
Highway Speeds MediumWarmTwo
City Traffic Maximum GCWR -Three
Highway Speeds Maximum GCWR -Four
Uphill Grade Maximum GCWR HotFive
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STARTING AND OPERATING231
(Continued)
NOTE:
Light duty operation such as light trailer towing
or no load operation will extend the time before
the engine is at full efficiency. Reduced fuel
economy and power may be seen at this time.
For additional vehicle break-in requirements,
refer to “Trailer Towing” in “Starting And
Operating” of the Owners Manual.
Because of the construction of the Cummins®
Turbo Diesel engine, engine run-in is enhanced
by loaded operating conditions which allow the
engine parts to achieve final finish and fit during
the first 6,000 miles (10,000 km).
PARKING BRAKE
Before leaving the vehicle, make sure that the
parking brake is fully applied. Also, be certain to
leave the transmission in PARK.
The foot-operated parking brake is located
below the lower left corner of the instrument
panel. To apply the park brake, firmly push the
park brake pedal fully. To release the parking
brake, pull the parking brake release handle.
Parking Brake Release

When the parking brake is applied with the
ignition switch ON, the “Brake Warning Light” in
the instrument cluster will illuminate.
NOTE:When the parking brake is applied and the
transmission is placed in gear, the “Brake
Warning Light” will flash. If vehicle speed is
detected, a chime will sound to alert the
driver. Fully release the parking brake before
attempting to move the vehicle.
This light only shows that the parking brake is
applied. It does not show the degree of brake
application. 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.
The parking brake should always be applied
whenever the driver is not in the vehicle.
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.
Never leave children alone in a vehicle, or
with access to an unlocked vehicle. Leaving
unattended children in a vehicle is
dangerous for a number of reasons. A child
or others could be seriously or fatally
injured.
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232STARTING AND OPERATING
DIESEL EXHAUST BRAKE — ENGINE
BRAKING (IF EQUIPPED)
The purpose of the exhaust brake (engine
braking) feature is to supply negative (braking)
torque from the engine. Typically, the engine
braking is used for, but not limited to, vehicle
towing applications where vehicle braking can
be achieved by the internal engine power,
thereby sparing the mechanical brakes of the
vehicle.
Benefits of the exhaust brake are:
Vehicle driving control.
Reduced brake fade.
Longer brake life.
Faster cab warm-up.
The exhaust brake feature will only function
when the driver toggles it on by pushing the
exhaust brake button until the “Exhaust Brake
Indicator” is illuminated. Normal (Full Strength)
exhaust brake mode is indicated by a yellow
“Exhaust Brake Indicator”.
Exhaust Brake Switch

Once the “Exhaust Brake Indicator” is
illuminated and the vehicle is moving faster
than 5 mph (8 km/h); the exhaust brake will
automatically operate when the driver removes
pressure from the accelerator pedal. Exhaust
braking is most effective when the engine RPM
is higher. The automatic transmission will
downshift more aggressively in TOW/HAUL
mode when the exhaust brake is enabled to
increase brake performance.
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 cause 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)

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238STARTING AND OPERATING
conditions, using a lower gear range will
improve performance and extend transmission
life by reducing excessive shifting and heat
buildup.
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, 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. For
example, if you set the transmission gear limit
to 4 (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 GEAR – switch (on
the steering wheel) will activate ERS mode,
display the current gear in the instrument
cluster, and set that gear as the top available

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STARTING AND OPERATING239
gear. Once in ERS mode, tapping the GEAR – or
GEAR + switch will change the top available
gear.

ERS Control

To exit ERS mode, simply push and hold the
GEAR + switch until the gear limit display
disappears from the instrument cluster.When to Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer,
carrying a heavy load, etc., and frequent
transmission shifting occurs, push the TOW/
HAUL switch to activate TOW/HAUL mode. This
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.
SIX-SPEED AUTOMATIC TRANSMISSION
— I
F EQUIPPED
Pickup models may use either AISIN (AS69RC
HD) transmission, or the 68RFE transmission
(which has no PTO access cover).
The transmission gear position display (located
in the instrument cluster) indicates the
transmission gear range. The gear selector is
mounted on the right side of the steering
column. You must press the brake pedal to
move the gear selector out of PARK; refer to
“Brake/Transmission Shift Interlock System” in
this section. To drive, move the gear selector
from PARK or NEUTRAL to the DRIVE position.
Pull the gear selector toward you when shifting
into REVERSE or PARK, or when shifting out of
PARK.
1 — GEAR + Switch
2 — GEAR – Switch
WARNING!
Do not downshift for additional engine
braking 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
control, which may cause an accident
possibly resulting in personal injury or death.
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242STARTING AND OPERATING
NEUTRAL (N)
Use this range when the vehicle is standing for
prolonged periods with the engine running. The
engine may be started in this range. Apply the
parking brake and shift the transmission into
PARK if you must exit the vehicle. DRIVE (D)
This range should be used for most city and
highway driving. It provides the smoothest
upshifts and downshifts, and the best fuel
economy. The transmission automatically
upshifts through underdrive first, second, and
third gears, direct fourth gear and overdrive fifth
and sixth gears. The DRIVE position provides
optimum driving characteristics under all
normal operating conditions.
When frequent transmission shifting occurs
(such as when operating the vehicle under
heavy loading conditions, in hilly terrain,
traveling into strong head winds, or while towing
a heavy trailer), use the Electronic Range Select
(ERS) shift control refer to “Electronic Range
Select (ERS) Operation” in this section for
further information to select a lower gear range.
Under these conditions, using a lower gear
range will improve performance and extend
transmission life by reducing excessive shifting
and heat buildup.If the transmission temperature exceeds
normal operating limits, the powertrain
controller will modify the transmission shift
schedule and expand the range of torque
converter clutch engagement. This is done to
prevent transmission damage due to
overheating.
If the transmission becomes extremely hot or is
in danger of overheating, the “Transmission
Temperature Warning Light” may illuminate and
the transmission may operate differently until
the transmission cools down.
NOTE:
Use caution when operating a heavily loaded
vehicle at low speeds (such as towing a trailer
up a steep grade, or in stop-and-go traffic)
during hot weather. In these conditions, torque
converter slip can impose a significant addi
-
tional heat load on the cooling system. Down -
shifting the transmission to the lowest possible
gear (when climbing a grade), or shifting to
NEUTRAL (when stopped in heavy traffic) can
help to reduce this excess heat generation.
WARNING!
Do not coast in NEUTRAL and never turn off
the ignition to coast down a hill. These are
unsafe practices that limit your response to
changing traffic or road conditions. You might
lose control of the vehicle and have a
collision.
CAUTION!
Towing the vehicle, coasting, or driving for any
other reason with the transmission in
NEUTRAL can cause severe transmission
damage. Refer to “Recreational Towing” in
“Starting And Operating” and “Towing A
Disabled Vehicle” in “In Case Of Emergency”
for further information.

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STARTING AND OPERATING243
During cold temperatures, transmission
operation may be modified depending on
engine and transmission temperature as well
as vehicle speed. This feature improves warm
up time of the engine and transmission to
achieve maximum efficiency. Engagement of
the torque converter clutch is inhibited until the
transmission fluid is warm refer to the “Note”
under “Torque Converter Clutch” in this section.
On Pickup models with 68RFE transmission, top
overdrive gear is also inhibited until the
transmission fluid is warm, and during
extremely cold temperatures (-16°F [-27°C] or
below), operation may briefly be limited to first
and direct gears only. On trucks with AISIN
(AS69RC) transmission, fifth and sixth gears
may be inhibited briefly on cold starts below
41°F (5°C), and during very cold temperatures
(-4°F [-20°C] or below), operation may briefly
be limited to third gear only. During this
condition, the ability of the vehicle to accelerate
under heavily loaded conditions may be
reduced. In all cases, 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 remains
in fourth gear (for 68RFE transmission) or third
gear (for AISIN (AS69RC) transmission)
regardless of which forward gear is selected. If an
AISIN (AS69RC)-equipped truck enters Limp
Home Mode at highway speeds, it will initially
engage fifth gear, until the vehicle slows to a
speed where third gear can be engaged. PARK,
REVERSE, and NEUTRAL will continue to operate.
The Malfunction Indicator Light (MIL) may be
illuminated. Limp Home Mode allows the vehicle
to be driven to an authorized dealer for service
without damaging the transmission.

In the event of a momentary problem, the
transmission can be reset to regain all forward
gears by performing the following steps:

1. Stop the vehicle.

2. Shift the transmission into PARK.
3. Turn the ignition off.
4. Wait approximately 10 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, 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. For
example, if you set the transmission gear limit
to 4 (FOURTH gear), the transmission will not
shift above FOURTH gear, but will shift through
the lower gears normally.
You can switch between DRIVE and ERS mode
at any vehicle speed. When the gear selector is
in the DRIVE position, the transmission will
operate automatically, shifting between all
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