engine Ram 3500 2020 Service Manual

132GETTING TO KNOW YOUR INSTRUMENT PANEL
Hood Open Warning Light
This warning light will illuminate when
the hood is ajar/open and not fully
closed.
NOTE:
If the vehicle is moving, there will also be a
single chime.
Vehicle Security Warning Light — If
Equipped
This light will flash at a fast rate for
approximately 15 seconds when the
vehicle security alarm is arming, and
then will flash slowly until the vehicle
is disarmed.
Engine Coolant Temperature Warning
Light
This warning light warns of an
overheated engine condition. If the
engine coolant temperature is too
high, this indicator will illuminate and
a single chime will sound. If the temperature
reaches the upper limit, a continuous chime will
sound for four minutes or until the engine is
able to cool; whichever comes first. If the light turns on while driving, safely pull over
and stop the vehicle. If the Air Conditioning
(A/C) system is on, turn it off. Also, shift the
transmission into NEUTRAL and idle the vehicle.
If the temperature reading does not return to
normal, turn the engine off immediately and call
for service.
Refer to “If Your Engine Overheats” in “In Case
Of Emergency” for further information.
Battery Charge Warning Light
This warning light will illuminate when
the battery is not charging properly. If
it stays on while the engine is running,
there may be a malfunction with the
charging system. Contact an authorized dealer
as soon as possible.
This indicates a possible problem with the
electrical system or a related component.
Oil Pressure Warning Light
This warning light will illuminate to
indicate low engine oil pressure. If the
light turns on while driving, stop the
vehicle, shut off the engine as soon as
possible, and contact an authorized dealer. A
chime will sound when this light turns on. Do not operate the vehicle until the cause is
corrected. This light does not indicate how
much oil is in the engine. The engine oil level
must be checked under the hood.
Oil Temperature Warning Light
This warning light will illuminate to
indicate the engine oil temperature is
high. If the light turns on while driving,
stop the vehicle and shut off the
engine as soon as possible. Wait for oil
temperature to return to normal levels.
Electronic Throttle Control (ETC) Warning
Light
This warning light will illuminate to
indicate a problem with the Electronic
Throttle Control (ETC) system. If a
problem is detected while the vehicle
is running, the light will either stay on or flash
depending on the nature of the problem. Cycle
the ignition when the vehicle is safely and
completely stopped and the transmission is
placed in the PARK (P) position. The light should
turn off. If the light remains on with the vehicle
running, your vehicle will usually be drivable;
however, see an authorized dealer for service
as soon as possible.

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GETTING TO KNOW YOUR INSTRUMENT PANEL133
NOTE:
This light may turn on if the accelerator and
brake pedals are pressed at the same time.
If the light continues to flash when the vehicle is
running, immediate service is required and you
may experience reduced performance, an
elevated/rough idle, or engine stall and your
vehicle may require towing. The light will come
on when the ignition is placed in the ON/RUN or
ACC/ON/RUN position and remain on briefly as
a bulb check. If the light does not come on
during starting, have the system checked by an
authorized dealer.
Trailer Brake Disconnected Warning Light
This warning light will illuminate when
the Trailer Brake has been
disconnected.
Refer to “Trailer Towing” in “Starting And
Operating” for further information.
Transmission Temperature Warning Light
— If Equipped
This warning light will illuminate to
warn of a high transmission fluid
temperature. This may occur with
strenuous usage such as trailer towing. If this light turns on, stop the vehicle and
run the engine at idle or slightly faster, with the
transmission in PARK (P) or NEUTRAL (N), until
the light turns off. Once the light turns off, you
may continue to drive normally.
Door Open Warning Light
This indicator will illuminate when a
door is ajar/open and not fully closed.
NOTE:
If the vehicle is moving there will also be a single
chime.
YELLOW WARNING LIGHTS
Adaptive Cruise Control (ACC) Fault
Warning Light — If Equipped
This warning light will illuminate to
indicate a fault in the ACC system.
Contact a local authorized dealer for
service.
For further information, refer to “Adaptive
Cruise Control (ACC)” in “Starting And
Operating.”
Air Suspension Fault Warning Light — If
Equipped
This light will illuminate when a fault is
detected with the air suspension
system.
Refer to “Air Suspension System — If Equipped”
in “Starting And Operating” for further
information.
Engine Check/Malfunction Indicator
Warning Light (MIL)
The Engine Check/Malfunction
Indicator Light (MIL) is a part of an
Onboard Diagnostic System called
OBD II that monitors engine and
WARNING!
If you continue operating the vehicle when
the Transmission Temperature Warning Light
is illuminated you could cause the fluid to boil
over, come in contact with hot engine or
exhaust components and cause a fire.
CAUTION!
Continuous driving with the Transmission
Temperature Warning Light illuminated will
eventually cause severe transmission
damage or transmission failure.
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134GETTING TO KNOW YOUR INSTRUMENT PANEL
automatic transmission control systems. This
warning light will illuminate when the ignition is
in the ON/RUN position before engine start. If
the bulb does not come on when turning the
ignition switch from OFF to ON/RUN, have the
condition checked promptly.
Certain conditions, such as a loose or missing
gas cap, poor quality fuel, etc., may illuminate
the light after engine start. The vehicle should
be serviced if the light stays on through several
typical driving styles. In most situations, the
vehicle will drive normally and will not require
towing.
When the engine is running, the MIL may flash
to alert serious conditions that could lead to
immediate loss of power or severe catalytic
converter damage. The vehicle should be
serviced by an authorized dealer as soon as
possible if this occurs.Electronic Stability Control (ESC) Active
Warning Light — If Equipped
This warning light will indicate when
the Electronic Stability Control system
is Active. The “ESC Indicator Light” in
the instrument cluster will come on
when the ignition is placed in the ON/RUN or
ACC/ON/RUN position, and when ESC is
activated. It should go out with the engine
running. If the “ESC Indicator Light” comes on
continuously with the engine running, a
malfunction has been detected in the ESC
system. If this warning light remains on after
several ignition cycles, and the vehicle has been
driven several miles (kilometers) at speeds
greater than 30 mph (48 km/h), see an
authorized dealer as soon as possible to have
the problem diagnosed and corrected.
The “ESC OFF Indicator Light” and the “ESC
Indicator Light” come on momentarily each
time the ignition is placed in the ON/RUN or
ACC/ON/RUN position.
WARNING!
A malfunctioning catalytic converter, as
referenced above, can reach higher
temperatures than in normal operating
conditions. This can cause a fire if you drive
slowly or park over flammable substances
such as dry plants, wood, cardboard, etc. This
could result in death or serious injury to the
driver, occupants or others.
CAUTION!
Prolonged driving with the Malfunction
Indicator Light (MIL) on could cause damage
to the vehicle control system. It also could
affect fuel economy and driveability. If the
MIL is flashing, severe catalytic converter
damage and power loss will soon occur.
Immediate service is required.

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GETTING TO KNOW YOUR INSTRUMENT PANEL135
The ESC system will make buzzing or clicking
sounds when it is active. This is normal; the
sounds will stop when ESC becomes inactive.
This light will come on when the vehicle is in
an ESC event.
Electronic Stability Control (ESC) OFF
Warning Light — If Equipped
This warning light indicates the
Electronic Stability Control (ESC) is
off.
Each time the ignition is turned to ON/RUN or
ACC/ON/RUN, the ESC system will be on, even
if it was turned off previously.
LaneSense Warning Light — If Equipped
The LaneSense system provides the
driver with visual and steering torque
warnings when the vehicle starts to
drift out of its lane unintentionally
without the use of a turn signal.
When the LaneSense system senses a lane
drift situation, the LaneSense indicator
changes from solid green to solid yellow.
When the LaneSense system senses the lane
has been approached and is in a lane depar -
ture situation, the LaneSense indicator
changes from solid white/green to flashing
yellow.
Refer to “LaneSense – If Equipped” in
“Starting And Operating” for further informa -
tion.
Service LaneSense Warning Light — If
Equipped
This warning light will illuminate when
the LaneSense system is not
operating and requires service.
Please see an authorized dealer.
Low Washer Fluid Warning Light
This warning light will illuminate when
the windshield washer fluid is low.
Refer to “Engine Compartment” in
“Servicing And Maintenance” for further
information.
Low Fuel Warning Light
When the fuel level reaches
approximately 3.2 gal (12 L) this light
will turn on, and remain on until fuel is
added.
A single warning chime will sound with Low Fuel
Warning.
Low Coolant Level Warning Light
This telltale will turn on to indicate the
vehicle coolant level is low.
Refer to “Fluids And Lubricants” in
“Technical Specifications” for further
information.
Loose Fuel Filler Cap Warning Light — If
Equipped
This warning light will illuminate when
the fuel filler cap is loose. Properly
close the filler cap to disengage the
light. If the light does not turn off,
please see an authorized dealer.
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138GETTING TO KNOW YOUR INSTRUMENT PANEL
YELLOW INDICATOR LIGHTS
Forward Collision Warning Off Indicator
Light — If Equipped
This indicator light illuminates to
indicate that Forward Collision
Warning is off.
Refer to “Auxiliary Driving Systems” in “Safety”
for further information.
Air Suspension Payload Protection
Indicator Light — If Equipped
This indicator light will illuminate to
indicate that the maximum payload
may have been exceeded or load
leveling cannot be achieved at its
current ride height. Protection Mode will
automatically be selected in order to “protect”
the air suspension system, air suspension
adjustment is limited due to payload.
TOW/HAUL Indicator Light
This indicator light will illuminate
when TOW/HAUL mode is selected.
Refer to “Trailer Towing” in “Starting
And Operating” for further information.
Cargo Light — If Equipped
This indicator light will illuminate
when the cargo light is activated by
pushing the cargo light button on the
headlight switch.
Cold Ambient Derate Mode Indicator Light
— If Equipped
This indicator light will illuminate
when a derate (engine power
reduction) is activated for protection
of the turbocharger in cold ambient
temperatures.
For further information, refer to “Instrument
Cluster Display” in “Getting To Know Your
Instrument Panel”.
Diesel Exhaust Brake Indicator Light — If
Equipped
This indicator light will illuminate
when the Diesel Exhaust Brake has
been activated, and is in full strength
mode.
Refer to “Diesel Exhaust Brake (Engine
Braking)” in “Starting And Operating” for further
information.
Sway Bar Indicator Light — If Equipped
This indicator light will illuminate
when the front sway bar is
disconnected.
Refer to “Stabilizer/Sway Bar System — Power
Wagon Only” in “Starting And Operating” for
further information.
Snowplow Mode Indicator Light — If
Equipped
This indicator light will illuminate
when Snowplow Mode has been
activated.
Refer to “Snowplow” in “Starting And
Operating” for further information.
Air Suspension Alternate Trailer Height
Indicator Light — If Equipped
This light will illuminate when the air
suspension system is set to the
Alternate Trailer Height setting.
Refer to “Air Suspension System — If Equipped”
in “Starting And Operating” for further
information.

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140GETTING TO KNOW YOUR INSTRUMENT PANEL
Low Diesel Exhaust Fluid (DEF) Indicator
Light — If Equipped
The Low Diesel Exhaust Fluid (DEF)
Indicator will illuminate if the vehicle
is low on Diesel Exhaust Fluid (DEF).
Refer to “Starting And Operating” for
further information.
Wait To Start Light — If Equipped
This indicator light will illuminate for
approximately two seconds when the
ignition is turned to the RUN position.
Its duration may be longer based on
colder operating conditions. Vehicle will not
initiate start until telltale is no longer displayed.
Refer to “Starting The Engine” in “Starting And
Operating” for further information.
NOTE:
The “Wait To Start” telltale may not illuminate if
the intake manifold temperature is warm
enough.
Water In Fuel Indicator Light — If Equipped
The “Water In Fuel Indicator Light” will
illuminate when there is water
detected in the fuel filter. If this light
remains on, DO NOT start the vehicle before you drain the water from the fuel filter to
prevent engine damage.
Refer to the “Draining Fuel/Water Separator
Filter” section in “Dealer Service” in “Servicing
And Maintenance” for further information.
GREEN INDICATOR LIGHTS
Adaptive Cruise Control (ACC) Set With
Target Light — If Equipped
This will display when the ACC is set
and a target vehicle is detected.
Refer to “Adaptive Cruise Control
(ACC) — If Equipped” in “Starting And Operating”
for further information.
Adaptive Cruise Control (ACC) Set With No
Target Detected Indicator Light — If
Equipped
This light will turn on when the
Adaptive Cruise Control is SET and
there is no target vehicle detected.
Refer to "Adaptive Cruise Control (ACC) — If
Equipped" in "Starting And Operating" for
further information.
Automatic Diesel Exhaust Brake Indicator
Light — If Equipped
This indicator light will illuminate
when the Diesel Exhaust Brake has
been activated, and has switched to
Automatic mode.
Refer to “Diesel Exhaust Brake — Engine
Braking (If Equippes)” in “Starting And
Operating” for further information.
ECO Mode Indicator Light
This light will turn on when ECO Mode
is active.
Park/Headlight On Indicator Light
This indicator light will illuminate
when the park lights or headlights are
turned on.
Refer to “Exterior Lights” in “Getting To Know
Your Vehicle” for further information.
LaneSense Indicator Light — If Equipped
The LaneSense indicator light
illuminates solid green when both
lane markings have been detected
and the system is “armed” and ready

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142GETTING TO KNOW YOUR INSTRUMENT PANEL
BLUE INDICATOR LIGHTS
High Beam Indicator Light
This indicator light will illuminate to
indicate that the high beam
headlights are on. With the low beams
activated, push the multifunction
lever forward (toward the front of the vehicle) to
turn on the high beams. Pull the multifunction
lever rearward (toward the rear of the vehicle) to
turn off the high beams. If the high beams are
off, pull the lever toward you for a temporary
high beam on, "flash to pass" scenario.
ONBOARD DIAGNOSTIC SYSTEM — OBD II
Your vehicle is equipped with a sophisticated
Onboard Diagnostic system called OBD II. This
system monitors the performance of the
emissions, engine, and transmission control
systems. When these systems are operating
properly, your vehicle will provide excellent
performance and fuel economy, as well as
engine emissions well within current
government regulations.
If any of these systems require service, the OBD
II system will turn on the Malfunction Indicator
Light (MIL). It will also store diagnostic codes and other information to assist your service
technician in making repairs. Although your
vehicle will usually be drivable and not need
towing, see an authorized dealer for service as
soon as possible.
ONBOARD DIAGNOSTIC SYSTEM
(OBD II) C
YBERSECURITY
Your vehicle is required to have an Onboard
Diagnostic system (OBD II) and a connection
port to allow access to information related to
the performance of your emissions controls. Authorized service technicians may need to
access this information to assist with the
diagnosis and service of your vehicle and
emissions system.
For further information, refer to “Cybersecurity”
in “Multimedia”.
CAUTION!
Prolonged driving with the MIL on could
cause further damage to the emission
control system. It could also affect fuel
economy and driveability. The vehicle must
be serviced before any emissions tests can
be performed.
If the MIL is flashing while the vehicle is
running, severe catalytic converter damage
and power loss will soon occur. Immediate
service is required.
WARNING!
ONLY an authorized service technician
should connect equipment to the OBD II
connection port in order to read the VIN,
diagnose, or service your vehicle.
If unauthorized equipment is connected to
the OBD II connection port, such as a
driver-behavior tracking device, it may:
Be possible that vehicle systems,
including safety related systems, could
be impaired or a loss of vehicle control
could occur that may result in an acci
-
dent involving serious injury or death.
Access, or allow others to access, infor -
mation stored in your vehicle systems,
including personal information.

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GETTING TO KNOW YOUR INSTRUMENT PANEL143
EMISSIONS INSPECTION AND
MAINTENANCE PROGRAMS
In some localities, it may be a legal requirement
to pass an inspection of your vehicle's
emissions control system. Failure to pass could
prevent vehicle registration.
For states that require an Inspection
and Maintenance (I/M), this check
verifies the “Malfunction Indicator
Light (MIL)” is functioning and is not
on when the engine is running, and that the
OBD II system is ready for testing.
Normally, the OBD II system will be ready. The
OBD II system may not be ready if your vehicle
was recently serviced, recently had a depleted
battery or a battery replacement. If the OBD II
system should be determined not ready for the
I/M test, your vehicle may fail the test.
Your vehicle has a simple ignition actuated test,
which you can use prior to going to the test
station. To check if your vehicle's OBD II system
is ready, you must do the following:
1. Cycle the ignition switch to the ON position,
but do not crank or start the engine.

NOTE:
If you crank or start the engine, you will have to
start this test over.
2. As soon as you cycle the ignition switch to the ON position, you will see the
“Malfunction Indicator Light (MIL)” symbol
come on as part of a normal bulb check.
3. Approximately 15 seconds later, one of two things will happen:
The MIL will flash for about 10 seconds and then return to being fully illuminated
until you turn OFF the ignition or start the
engine. This means that your vehicle's
OBD II system is not ready and you
should not proceed to the I/M station.
The MIL will not flash at all and will remain
fully illuminated until you place the ignition in
the off position or start the engine. This
means that your vehicle's OBD II system is
ready and you can proceed to the I/M station. If your OBD II system is not ready,
you should
see an authorized dealer or repair facility. If your
vehicle was recently serviced or had a battery
failure or replacement, you may need to do
nothing more than drive your vehicle as you
normally would in order for your OBD II system
to update. A recheck with the above test routine
may then indicate that the system is now ready.
Regardless of whether your vehicle's OBD II
system is ready or not, if the MIL is illuminated
during normal vehicle operation you should
have your vehicle serviced before going to the
I/M station. The I/M station can fail your vehicle
because the MIL is on with the engine running.
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146SAFETY
(Continued)
If the “Brake System Warning Light” remains on
or comes on while driving, it indicates that the
brake system is not functioning properly and
that immediate service is required. If the “Brake
System Warning Light” does not come on when
the ignition is placed in the ON/RUN mode,
have the light repaired as soon as possible.
Electronic Brake Force Distribution (EBD)
This function manages the distribution of the
braking torque between the front and rear axles
by limiting braking pressure to the rear axle.
This is done to prevent overslip of the rear
wheels to avoid vehicle instability, and to
prevent the rear axle from entering Anti-Lock
Brake System (ABS) before the front axle.
Electronic Stability Control (ESC)
This system enhances directional control and
stability of the vehicle under various driving
conditions. Electronic Stability Control (ESC)
corrects for oversteering or understeering of the
vehicle by applying the brake of the appropriate
wheel(s) to assist in counteracting the oversteer
or understeer condition. Engine power may also
be reduced to help the vehicle maintain the
desired path.ESC uses sensors in the vehicle to determine
the vehicle path intended by the driver and
compares it to the actual path of the vehicle.
When the actual path does not match the
intended path, ESC applies the brake of the
appropriate wheel to assist in counteracting the
oversteer or understeer condition.

Oversteer — when the vehicle is turning
more than appropriate for the steering
wheel position.
Understeer — when the vehicle is turning
less than appropriate for the steering wheel
position.

The “ESC Activation/Malfunction Indicator
Light” located in the instrument cluster will start
to flash as soon as the ESC system becomes
active. The “ESC Activation/Malfunction
Indicator Light” also flashes when the TCS is
active. If the “ESC Activation/Malfunction
Indicator Light” begins to flash during
acceleration, ease up on the accelerator and
apply as little throttle as possible. Be sure to
adapt your speed and driving to the prevailing
road conditions.
WARNING!
Electronic Stability Control (ESC) cannot
prevent the natural laws of physics from
acting on the vehicle, nor can it increase
the traction afforded by prevailing road
conditions. ESC cannot prevent accidents,
including those resulting from excessive
speed in turns, driving on very slippery
surfaces, or hydroplaning. ESC also cannot
prevent accidents resulting from loss of
vehicle control due to inappropriate driver
input for the conditions. Only a safe, atten -
tive, and skillful driver can prevent acci -
dents. The capabilities of an ESC equipped
vehicle must never be exploited in a reck -
less or dangerous manner which could
jeopardize the user’s safety or the safety of
others.

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SAFETY147
ESC Operating Modes
NOTE:
Depending upon model and mode of operation,
the ESC system may have multiple operating
modes. ESC On
This is the normal operating mode for the ESC.
Whenever the vehicle is started, the ESC system
will be in this mode. This mode should be used
for most driving conditions. Alternate ESC
modes should only be used for specific reasons
as noted in the following paragraphs.
Partial Off
The “Partial Off” mode is intended for times
when a more spirited driving experience is
desired. This mode may modify TCS and ESC
thresholds for activation, which allows for more
wheel spin than normally allowed. This mode
may be useful if the vehicle becomes stuck.
To enter the “Partial Off” mode, momentarily
push the “ESC OFF” switch and the “ESC OFF
Indicator Light” will illuminate. To turn the ESC
on again, momentarily push the “ESC OFF”
switch and the “ESC OFF Indicator Light” will
turn off.
NOTE:
For vehicles with multiple partial ESC modes, a
momentary button push will toggle the ESC
mode. Multiple momentary button pushes may
be required to return to ESC On.
Vehicle modifications, or failure to properly
maintain your vehicle, may change the
handling characteristics of your vehicle,
and may negatively affect the performance
of the ESC system. Changes to the steering
system, suspension, braking system, tire
type and size or wheel size may adversely
affect ESC performance. Improperly
inflated and unevenly worn tires may also
degrade ESC performance. Any vehicle
modification or poor vehicle maintenance
that reduces the effectiveness of the ESC
system can increase the risk of loss of
vehicle control, vehicle rollover, personal
injury and death.
WARNING!
(Continued)
WARNING!
When in “Partial Off” mode, the TCS func -
tionality of ESC, (except for the limited slip
feature described in the TCS section), has
been disabled and the “ESC Off Indicator
Light” will be illuminated. When in “Partial
Off” mode, the engine power reduction
feature of TCS is disabled, and the
enhanced vehicle stability offered by the
ESC system is reduced.
Trailer Sway Control (TSC) is disabled when
the ESC system is in the “Partial Off” mode.
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