2020 Ram 4500 Chassis Cab Service

210STARTING AND OPERATING
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 over -
heating.
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. During cold temperatures, transmission opera
-
tion 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 transmis -
sion fluid is warm (refer to the “Note” under
“Torque Converter Clutch” in this section).
On trucks with AS66RC or AS69RC transmis -
sion, 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 electroni -
cally for abnormal conditions. If a condition is
detected that could result in transmission
damage, Transmission Limp Home Mode is acti -
vated. In this mode, the transmission remains
in third gear (for AS66RC/AS69RC transmis -
sion) regardless of which forward gear is
selected. If an AS66RC/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 trans
-
mission 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 to the OFF position.
4. Wait approximately 10 seconds.
5. Restart the engine.
6. Shift into the desired gear range. If the problem is no longer detected, the trans -
mission will return to normal operation.

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STARTING AND OPERATING211
NOTE:
Even if the transmission can be reset, we
recommend that you visit your authorized
dealer at your earliest possible convenience.
Your authorized dealer has diagnostic equip -
ment to assess the condition of your trans -
mission.
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
available gears. Tapping the ERS (-) switch 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
(-) or (+) will change the top available gear.

Electronic Range Select
To exit ERS mode, simply push and hold the ERS
(+) switch until the gear limit display disappears
from the instrument cluster.
NOTE:
To select the proper gear position for maximum
deceleration (engine braking), simply push and
hold the ERS (-) switch. The transmission will
shift to the range from which the vehicle can
best be slowed down.
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.
CAUTION!
When using ERS for engine braking while
descending steep grades, be careful not to
overspeed the engine. Apply the brakes as
needed to prevent engine overspeed.
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STARTING AND OPERATING217

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 trans -
mission 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
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 disap -
pears from the instrument cluster.
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.
5

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220STARTING AND OPERATING
This electronically shifted transfer case is
designed to be driven in the two–wheel drive
position (2WD) for normal street and highway
conditions on dry hard surfaced roads. Driving
the vehicle in 2WD will have greater fuel
economy benefits as the front axle is not
engaged in 2WD.
When additional traction is required, the
transfer case 4WD HIGH and 4WD LOW posi -
tions 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 pushing the desired position
on the 4WD control switch.
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 posi -
tions on dry hard surfaced roads may cause
increased tire wear and damage to the driveline
components. 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 Proce-
dure” 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 illumi -
nates during driving, it means that the
four-wheel drive system is not functioning prop -
erly and that service is required.

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224STARTING AND OPERATING
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 illumi
-
nates during driving, it means that the
four-wheel drive system is not functioning prop -
erly 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). Proper operation of four-wheel drive vehicles
depends on tires of equal size, type and circum
-
ference 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. To retry a shift: return the
control switch back to the original position,
make certain all shift requirements have
been met, wait five seconds and try the shift
again.
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.

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STARTING AND OPERATING229
POWER STEERING
Hydraulic Power Steering
The standard power steering system will give
you good vehicle response and increased ease
of maneuverability in tight spaces. The system
will provide mechanical steering capability if
power assist is lost.
If for some reason the power assist is inter -
rupted, it will still be possible to steer your
vehicle. Under these conditions, you will
observe a substantial increase in steering
effort, especially at very low vehicle speeds and
during parking maneuvers.
NOTE:
Increased noise levels at the end of the
steering wheel travel are considered normal
and do not indicate that there is a problem
with the power steering system.
Upon initial start-up in cold weather, the
power steering pump may make noise for a
short amount of time. This is due to the cold,
thick fluid in the steering system. This noise
should be considered normal, and it does not
in any way damage the steering system.
Power Steering Fluid Check
Checking the power steering fluid level at a
defined service interval is not required. The fluid
should only be checked if a leak is suspected,
abnormal noises are apparent, and/or the
system is not functioning as anticipated. Check
fluid level when the engine is cold and off. Coor -
dinate inspection efforts through an authorized
dealer. If necessary, add fluid to restore to the proper
indicated level. With a clean cloth, wipe any
spilled fluid from all surfaces. Refer to “Fluids
And Lubricants” in “Technical Specifications”
for further information.
CAUTION!
Prolonged operation of the steering system at
the end of the steering wheel travel will
increase the steering fluid temperature and it
should be avoided when possible. Damage to
the power steering pump may occur.
WARNING!
Fluid level should be checked on a level
surface and with the engine off to prevent
injury from moving parts and to ensure
accurate fluid level reading. Do not overfill.
Use only manufacturer's recommended
power steering fluid.
CAUTION!
Do not use chemical flushes in your power
steering system as the chemicals can
damage your power steering components.
Such damage is not covered by the New
Vehicle Limited Warranty.5

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STARTING AND OPERATING241
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 tempo -
rarily 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 wind -
shield, driving directly into the sun and fog on
the inside of glass. In these cases, the instru -
ment cluster display will show “ACC/FCW
Limited Functionality Clean Front Windshield”
and the system will have degraded perfor -
mance.
The “ACC/FCW Limited Functionality Clean
Front Windshield” 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. If weather conditions are not a factor, the driver
should examine the windshield and the camera
located on the back side of the inside rear view
mirror. They may require cleaning or removal of
an obstruction.
When the condition that created limited func
-
tionality is no longer present, the system will
return to full functionality.
NOTE:
If the “ACC/FCW Limited Functionality Clean
Front Windshield” message occurs frequently
(e.g. more than once on every trip) without any
snow, rain, mud, or other obstruction, have the
windshield and forward facing camera
inspected at your authorized dealer.
Service ACC/FCW Warning
If the system turns off, and the instrument
cluster displays “ACC/FCW Unavailable Service
Required” or “Cruise/FCW Unavailable Service
Required”, there may be an internal system
fault or a temporary malfunction that limits ACC
functionality. Although the vehicle is still driv -
able under normal conditions, ACC will be
temporarily unavailable. If this occurs, try acti -
vating ACC again later, following an ignition
cycle. If the problem persists, see your autho -
rized dealer.
Precautions While Driving With ACC
In certain driving situations, ACC may have
detection issues. In these cases, ACC may
brake late or unexpectedly. The driver needs to
stay alert and may need to intervene.
NOTE:
Aftermarket add-ons such as snow plows, lift
kits, and brush/grille bars can hinder module
performance. Ensure the radar/camera has
no obstructions in the field of view.
Height modifications can limit module perfor -
mance and functionality.
Do not put stickers or easy passes over the
camera/radar field of view.
Any modifications to the vehicle that may
obstruct the field of view of the radar/camera
are not recommended.
Cleaning Instructions
Dust and dirt can accumulate on the cover and
block the camera lens. Clean the camera lens
with a soft microfiber cloth, being careful not to
damage or scratch the module.
5

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STARTING AND OPERATING249
Adjustable Chime Volume Settings
The rear chime volume settings are program -
mable through the Uconnect system. Refer to
“Uconnect Settings” in “Multimedia” for further
information.
The chime volume settings include low,
medium, and high. The factory default volume is
medium.
Enabling And Disabling ParkSense
ParkSense can be enabled and disabled with
the ParkSense switch.
When the gear selector is moved to
REVERSE and the system is disabled,
the instrument cluster display will
show the vehicle graphic with “Off”
over the arcs for as long as the vehicle is in
REVERSE.
NOTE:
The ParkSense system will automatically
disable when the system detects that a trailer
with trailer brakes has been connected to the
Integrated Trailer Brake Module. The instru -
ment cluster display will show an “Off” message
over the arcs if the ParkSense system is off, or
a “Trailer” message if the system is on, for as
long as the vehicle is in REVERSE. The ParkSense switch LED will be on when Park
-
Sense is disabled or defective. The ParkSense
switch LED will be off when the system is
enabled.
If the ParkSense switch is pushed, and the
system is disabled or requires service, the Park -
Sense switch LED will blink momentarily, and
then the LED will be on.
Service The ParkSense Rear Park Assist
System
During vehicle start up, when the Rear Park -
Sense System has detected a faulted condition,
the instrument cluster display will show the
"Rear ParkSense Unavailable Service Required"
or the "Rear ParkSense Unavailable Wipe
Sensors" message.
When the gear selector is moved into REVERSE,
a vehicle graphic will show in the instrument
cluster display, along with the display overlay
“Rear ParkSense Unavailable Wipe Sensors.” If
the system needs service, the display overlay
will read “Rear ParkSense Unavailable Service
Required” Under this condition, ParkSense will
not operate. If "Rear ParkSense Unavailable Wipe Sensors"
appears in the instrument cluster display make
sure the outer surface and the underside of the
rear fascia/bumper is clean and clear of snow,
ice, mud, dirt or other obstruction, and then
cycle the ignition. If the message continues to
appear, see an authorized dealer.
If "Rear ParkSense Unavailable Service
Required" appears in the instrument cluster
display, see an authorized dealer.Cleaning The ParkSense System
Clean the ParkSense sensors with water, car
wash soap and a soft cloth. Do not use rough or
hard cloths. Do not scratch or poke the sensors.
Otherwise, you could damage the sensors.
ParkSense System Usage Precautions
NOTE:
Ensure that the rear bumper is free of snow,
ice, mud, dirt and debris to keep the Park
-
Sense system operating properly.
Jackhammers, large trucks, and other vibra -
tions could affect the performance of Park -
Sense.
5

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