2021 RAM 1500 check engine light

13
Transmission Temperature Warning Light — If Equipped
Ú page 129
Door Open Warning Light Úpage 129
Yellow Warning Lights
Adaptive Cruise Control (ACC) Fault Warning
Light — If Equipped
Úpage 129
Air Suspension Fault Warning Light — If Equipped
Ú page 129
Engine Check/Malfunction Indicator Warning Light (MIL)
Ú page 130
Electronic Park Brake Warning Light Úpage 130
Electronic Stability Control (ESC) Active Warning Light — If Equipped
Úpage 130
Red Warning Lights
Electronic Stability Control (ESC) OFF Warning
Light — If Equipped
Úpage 131
Service LaneSense Warning Light — If Equipped Úpage 131
Low Washer Fluid Warning Light — If Equipped Úpage 131
Low Fuel Warning Light Úpage 131
Tire Pressure Monitoring System (TPMS) Warning Light
Ú page 131
Anti-Lock Brake System (ABS) Warning Light Úpage 132
Rear Axle Locker Fault Indicator Light — If Equipped
Ú page 132
Service Forward Collision Warning (FCW) Light — If Equipped
Ú page 132
Yellow Warning Lights
1

21_DT_OM_EN_USC_t.book Page 13

20GETTING TO KNOW YOUR VEHICLE
Programming And Requesting Additional
Key Fobs
Programming the key fob may be performed by
an authorized dealer.
NOTE:
Once a key fob is programmed to a vehicle, it
cannot be re-purposed and reprogrammed to
another vehicle.
Only key fobs that are programmed to the
vehicle electronics can be used to start and
operate the vehicle. Once a key fob is
programmed to a vehicle, it cannot be
programmed to any other vehicle.
Duplication of key fobs may be performed at an
authorized dealer. This procedure consists of
programming a blank key fob to the vehicle electronics. A blank key fob is one that has
never been programmed.
NOTE:
When having the Sentry Key Immobilizer system
serviced, bring all vehicle keys with you to an
authorized dealer Ú
page 482.
SENTRY KEY
The Sentry Key Immobilizer system prevents
unauthorized vehicle operation by disabling the
engine. The system does not need to be armed
or activated. Operation is automatic, regardless
of whether the vehicle is locked or unlocked.
The system uses a key fob, keyless push button
ignition and a Radio Frequency (RF) receiver to
prevent unauthorized vehicle operation.
Therefore, only key fobs that are programmed
to the vehicle can be used to start and operate
the vehicle. The system cannot reprogram a key
fob obtained from another vehicle.
After placing the ignition switch in the ON/RUN
position, the vehicle security light will turn on for
three seconds for a bulb check. If the light
remains on after the bulb check, it indicates
that there is a problem with the electronics. In
addition, if the light begins to flash after the
bulb check, it indicates that someone attempted to start the engine with an invalid key
fob. In the event that a valid key fob is used to
start the engine but there is an issue with the
vehicle electronics, the engine will start and
shut off after two seconds.
If the vehicle security light turns on during
normal vehicle operation (vehicle running for
longer than 10 seconds), it indicates that there
is a fault in the electronics. Should this occur,
have the vehicle serviced as soon as possible by
an authorized dealer.
All of the key fobs provided with your new
vehicle have been programmed to the vehicle
electronics Ú
page 482.
WARNING!
Always remove the key fobs from the
vehicle and lock all doors when leaving the
vehicle unattended.
For vehicles equipped with Keyless
Enter-N-Go — Ignition, always remember to
place the ignition in the OFF mode.
CAUTION!
The Sentry Key Immobilizer system is not
compatible with some aftermarket remote
starting systems. Use of these systems may
result in vehicle starting problems and loss of
security protection.

21_DT_OM_EN_USC_t.book Page 20

128GETTING TO KNOW YOUR INSTRUMENT PANEL
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 (N) and idle the
vehicle. If the temperature reading does not
return to normal, turn the engine off
immediately and call for service Ú page 389.
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 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 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.
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.

21_DT_OM_EN_USC_t.book Page 128

130GETTING TO KNOW YOUR INSTRUMENT PANEL
Engine Check/Malfunction Indicator
Warning Light (MIL)
The MIL is a part of an Onboard
Diagnostic System called OBD II that
monitors engine and 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 Park Brake Warning Light
This warning light will illuminate to
indicate the Electronic Park Brake is
not functioning properly and service is
required. Contact an authorized
dealer.
Electronic Stability Control (ESC) Active
Warning Light — If Equipped
This warning light will indicate when
the ESC 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 Indi -
cator Light come on momentarily each time
the ignition is placed in the ON/RUN or ACC/
ON/RUN position.
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.
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.

21_DT_OM_EN_USC_t.book Page 130

138GETTING TO KNOW YOUR INSTRUMENT PANEL
ONBOARD DIAGNOSTIC SYSTEM
(OBD II) C
YBERSECURITY
Your vehicle is required to have 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 Ú page 236.
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.
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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STARTING AND OPERATING141
(Continued)
NOTE:
Engine start up in very low ambient temperature
could result in evident white smoke. This condi -
tion will disappear as the engine warms up.
AUTOMATIC TRANSMISSION
Start the engine with the transmission in PARK
position. Apply the brake before shifting into any
driving range.
NOTE:
This vehicle is equipped with a transmission
shift interlocking system. The brake pedal
must be pressed to shift out of PARK.
If equipped with an 8-speed transmission,
starting the vehicle in NEUTRAL is not
possible unless the Manual Park Release has
been activated Ú page 390.
AUTOPARK
AutoPark is a supplemental feature to assist in
placing the vehicle in PARK should the
situations on the following pages occur. It is a
back up system and should not be relied upon as the primary method by which the driver shifts
the vehicle into PARK.
The conditions under which AutoPark will
engage are outlined on the following pages.
Do not leave the key fob in or near the
vehicle, or in a location accessible to chil-
dren, and do not leave the ignition of 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.
Do not leave children or animals inside
parked vehicles in hot weather. Interior
heat build-up may cause serious injury or
death.
CAUTION!
The engine is allowed to crank as long as
25 seconds. If the engine fails to start
during this period, please wait at least two
minutes for the starter to cool before
repeating start procedure.
WARNING!
(Continued)
If the “Water in Fuel Indicator Light”
remains on, DO NOT START engine before
you drain the water from the fuel filter to
avoid engine damage Ú page 412.
CAUTION! (Continued)
WARNING!
Driver inattention could lead to failure to
place the vehicle in PARK. ALWAYS DO A
VISUAL CHECK that your vehicle is in PARK
by verifying that a solid (not blinking) “P” is
indicated in the instrument cluster display
and near the gear selector. If the “P” indi -
cator is blinking, your vehicle is not in
PARK. As an added precaution, always
apply the parking brake when exiting the
vehicle.
AutoPark is a supplemental feature. It is not
designed to replace the need to shift your
vehicle into PARK. It is a back up system
and should not be relied upon as the
primary method by which the driver shifts
the vehicle into PARK.
4

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STARTING AND OPERATING149
NOTE:
Under certain conditions the engine fan will run
after the engine is turned off. These conditions
are under high load and high temperature
conditions.
Do Not Operate The Engine With Low Oil
Pressure
If the low oil pressure warning light turns on
while driving, stop the vehicle and shut down
the engine as soon as possible. A chime will
sound when the light turns on. NOTE:
Do not operate the vehicle until the cause is
corrected. This light does not show how much
oil is in the engine. The engine oil level must be
checked under the hood.
Do Not Operate The Engine With Failed
Parts
All engine failures give some warning before the
parts fail. Some important observations are:
Engine misfiring or vibrating severely
Sudden loss of power
Unusual engine noises
Fuel, oil or coolant leaks
Sudden change, outside the normal operating
range, in the engine operating temperature
Excessive smoke
Oil pressure drop
Driving Condition
Load Turbocharger Temperature Idle Time (min.) Before Engine
Shutdown
Stop and Go EmptyCoolNone
Stop and Go Medium 0.5
Highway Speeds MediumWarm 1.0
City Traffic Maximum GCWR 1.5
Highway Speeds Maximum GCWR 2.0
Uphill Grade Maximum GCWR Hot2.5
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.
4

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STARTING AND OPERATING151
ENGINE BREAK-IN RECOMMENDATIONS —
DIESEL ENGINE
The diesel engine does not require a break-in
period due to its construction. Normal operation
is allowed, providing the following
recommendations are followed:
Warm up the engine before placing it under
load.
Do not operate the engine at idle for
prolonged periods.
Observe vehicle oil pressure and tempera -
ture indicators.
Check the coolant and oil levels frequently.
Vary throttle position at highway speeds
when carrying or towing significant weight.
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.
The engine oil installed in the engine at the
factory is a high-quality energy conserving type
lubricant. Oil changes should be consistent with anticipated climate conditions under which
vehicle operations will occur. For the
recommended viscosity and quality grades
Ú
page 475.
NOTE:
NON-DETERGENT OR STRAIGHT MINERAL OILS
MUST NEVER BE USED.
PARKING BRAKE
ELECTRIC PARK BRAKE (EPB)
Your vehicle is equipped with an EPB that offers
simple operation, and some additional features
that make the parking brake more convenient
and useful.
The parking brake is primarily intended to
prevent the vehicle from rolling while parked.
Before leaving the vehicle, make sure that the
parking brake is applied. Also, be certain to
leave the transmission in PARK.
You can engage the parking brake in two ways:
Manually, by applying the parking brake
switch.
Automatically, by enabling the Auto Park
Brake feature in the customer programmable
features section of the Uconnect settings. The parking brake switch is located on the
instrument panel to the left of the steering
wheel (below the headlamp switch).

Electric Park Brake Switch

To apply the parking brake manually, pull up on
the switch momentarily. You may hear a slight
sound from the back of the vehicle while the
parking brake engages. Once the park brake is
fully engaged, the BRAKE telltale light in the
instrument cluster and an indicator on the
switch will illuminate. If your foot is on the brake
pedal while you apply the parking brake, you
may notice a small amount of brake pedal
movement. The parking brake can be applied
even when the ignition switch is OFF but the
BRAKE telltale light will not illuminate, however,
it can only be released when the ignition is in
the ON/RUN mode.
4

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