2020 Ram 3500 service

STARTING AND OPERATING229
Do Not Operate The Engine With Failed
Parts
All engine failures give some warning before the
parts fail. Be on the alert for changes in
performance, sounds, and visual evidence that
the engine requires service. Some important
clues are:
Engine misfiring or vibrating severely.
Sudden loss of power.
Unusual engine noises.
Fuel, oil or coolant leaks.
Sudden change, outside the normal oper -
ating range, in the engine operating tempera -
ture.
Excessive smoke.
Oil pressure drop.
ENGINE BLOCK HEATER — GAS ENGINE (IF
EQUIPPED)
The engine block heater warms the engine, and
permits quicker starts in cold weather. Connect
the cord to a standard 110-115 Volt AC
electrical outlet with a grounded, three-wire
extension cord.
The engine block heater cord is routed through
the grille by the right front tow hook.
It includes a removable cap that is secured by a
tethered strap. It also has a c-clip that is used
for storage when not in use for the Winter
months. During Winter months, remove the
heater cord wiring assembly from itself on the
c-clip.
The engine block heater must be plugged in at
least one hour to have an adequate warming
effect on the engine.
ENGINE BLOCK HEATER — DIESEL ENGINE
(IF EQUIPPED)
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.
The engine block heater cord is routed under
the hood to the right side and can be located
just behind the grille near the headlamp.
NOTE:
The engine block heater cord is a factory
installed option. If your vehicle is not equipped,
heater cords are available from an authorized
Mopar dealer.
The block heater must be plugged in at least
one hour to have an adequate warming effect
on the coolant.
CAUTION!
If oil pressure falls to less than normal
readings, shut the engine off immediately.
Failure to do so could result in immediate and
severe engine damage.
WARNING!
Remember to disconnect the engine block
heater cord before driving. Damage to the
110-115 Volt electrical cord could cause
electrocution.WARNING!
Remember to disconnect the cord before
driving. Damage to the 110–115 Volt
electrical cord could cause electrocution.
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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 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
5

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248STARTING AND OPERATING
NOTE:
The transfer case 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 NEUTRAL position is to
be used for recreational towing only. Refer to
“Recreational Towing” in “Starting And Oper -
ating” for further information.
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:
If All Of The Following Shift Conditions Are Met:

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 One Or More Of The Following Shift Conditions
Are Not Met:

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

2. The newly selected position indicator light will continue to flash.
3. The transfer case will not shift.
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. To find the shift
requirements, refer to the “Shifting Procedure”
for your transfer case, located in this section.
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.
Shifting Procedure
NOTE:
If any of the requirements to select a new
transfer case position have not been met, the
transfer case will not shift. The position indi
-
cator light for the previous position will
remain on and the newly selected position
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, the

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STARTING AND OPERATING251
When additional traction is required, the
transfer case 4WD HIGH and 4WD LOW
positions can be used to maximize torque to the
front driveshaft, forcing the front and rear
wheels to rotate at the same speed. This is
accomplished by rotating the 4WD Control
Switch to the desired position.
Refer to “Shifting Procedure” in this section for
specific shifting instructions.
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.
NOTE:
The transfer case NEUTRAL button is located on
the lower left hand corner of the 4WD Control
Switch. The transfer case NEUTRAL position is
to be used for recreational towing only. Refer to
“Recreational Towing” in “Starting And Oper -
ating” for further information. Transfer Case Position Indicator Lights
The Transfer Case Position Indicator Lights
(4WD and 4LOW) 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:
If All Of The Following Shift Conditions Are Met:


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 One Or More Of The Following Shift Conditions
Are Not Met:

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

2. The newly selected position indicator light will continue to flash.
3. The transfer case will not shift. 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, turn the control switch back to the
current position, wait five seconds, and retry
selection. To find the shift requirements, refer
to the "Shifting Procedure" for your transfer
case, located in this section.
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, as this can
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).
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256STARTING AND OPERATING
AIR SUSPENSION SYSTEM — IF EQUIPPED
DESCRIPTION
This air suspension system is a rear leveling ride
height system. The main purpose of this system
is to maintain the truck’s rear ride height level.
There are two selectable heights that can be
chosen based on your operating conditions.
The system requires that the ignition be in the
ON/RUN position or the engine running with
zero vehicle speed for all user requested
changes and load leveling.

Rear Leveling Ride Height Switch
Normal Ride Height (NRH)
– This is the standard
position of the suspension and is meant for
normal driving. It will automatically adjust to
maintain the rear ride height as conditions
change.
Alternate Trailer Height (ATH) – Lowers the
vehicle approximately 1 inch (25 mm) for a level
truck, to be used as required while trailer
towing. It will automatically adjust to maintain
the rear ride height as conditions change.
Trailer Decoupling/Unloading - The air
suspension system will continue to load level
after the vehicle has been turned off for
10 minutes without compressor activation. This
allows for easy removal of a trailer and/or load
from the back of the truck by maintaining the
ride height. After 10 minutes you will need to
turn the ignition to the run position for the air
suspension to re-level due to addition/removal
of load in the vehicle. If the air suspension
system is disabled using the settings menu (Tire
Jack Mode, Transport Mode, Alignment Mode,
or Bed Lowering Mode) the system will remain
disabled when the vehicle is turned off.
Reactivating the air suspension can be
accomplished via the settings menu or driving the vehicle above 5 mph (8 km/h) for Tire Jack
Mode, Alignment Mode, Transport Mode and
Bed Lowering Mode.
NOTE:
Most 3500 models will not lower to Alternate
Trailer Height (ATH) when unloaded.
Refer to “Trailer Towing” in “Starting And
Operating” for further information.
AIR SUSPENSION MODES
The air suspension system has multiple modes
to protect the system in unique situations:
Tire/Jack Mode
To assist with changing a tire, the air
suspension system has a feature which allows
the automatic leveling to be disabled. This
mode is intended to be enabled with the engine
running. Refer to “Instrument Cluster Display”
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.

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STARTING AND OPERATING257
in “Getting To Know Your Instrument Panel” or
“Uconnect Settings” in “Multimedia” (if
equipped with a touch screen radio) for further
information.
NOTE:
This mode is intended to be enabled with the
engine running.
Transport Mode
For towing your vehicle with four wheels off the
road, the air suspension system has a feature
which will put the vehicle below Normal Ride
Height (NRH) and disable the automatic load
leveling system. This mode is intended to be
enabled with engine running. Refer to
“Instrument Cluster Display” in “Getting To
Know Your Instrument Panel” or “Uconnect
Settings” in “Understanding Your Instrument
Panel” if equipped with a touch screen radio for
further information.
NOTE:
This mode is intended to be enabled with the
engine running. Wheel Alignment Mode
Before performing a wheel alignment this mode
must be enabled. Refer to “Instrument Cluster
Display” in “Getting To Know Your Instrument
Panel” or “Uconnect Settings” in “Multimedia”
(if equipped with a touch screen radio) for
further information.
NOTE:
This mode is intended to be enabled with the
engine running.
Bed Lowering Mode
This setting is used to lower the rear suspension
to the lowest possible height and disable the air
suspension system. It enables easier loading/
unloading of the truck and makes it easier to
hook up trailers. Refer to “Instrument Cluster
Display” in “Getting To Know Your Instrument
Panel” or “Uconnect Settings” in
“Understanding Your Instrument Panel” if
equipped with a touch screen radio for further
information.
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.
INSTRUMENT CLUSTER DISPLAY
M
ESSAGES
When the appropriate conditions exist, a
message will appear in the instrument cluster
display. Refer to “Instrument Cluster Display” in
“Getting To Know Your Instrument Panel” for
further information.
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.5

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