2021 RAM CHASSIS CAB warning light

SAFETY275
Electronic Brake Force Distribution (EBD)
EBD 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 ABS before the front axle.
Electronic Roll Mitigation (ERM)
ERM anticipates the potential for wheel lift by
monitoring the driver’s steering wheel input and
the speed of the vehicle. When ERM determines
that the rate of change of the steering wheel
angle and vehicle’s speed are sufficient to
potentially cause wheel lift, it then applies the
appropriate brake and may also reduce engine
power to lessen the chance that wheel lift will
occur. ERM can only reduce the chance of
wheel lift occurring during severe or evasive
driving maneuvers; it cannot prevent wheel lift
due to other factors, such as road conditions,
leaving the roadway, or striking objects or other
vehicles.
NOTE:
ERM is disabled any time the ESC is in “Full Off”
mode (if equipped). For a complete explanation
of the available ESC modes, see Ú page 275.
Electronic Stability Control (ESC)
ESC enhances directional control and stability
of the vehicle under various driving conditions.
ESC corrects for oversteering or understeering
of the vehicle by applying the brake of the
appropriate wheel(s) to counteract the above
conditions. Engine power may also be reduced
to help the vehicle maintain the desired path.

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.
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.

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!

Many factors, such as vehicle loading, road
conditions and driving conditions, influence
the chance that wheel lift or rollover may occur.
ERM cannot prevent all wheel lift or roll overs,
especially those that involve leaving the
roadway or striking objects or other vehicles.
The capabilities of an ERM-equipped vehicle
must never be exploited in a reckless or
dangerous manner which could jeopardize
the user's safety or the safety of others.

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276SAFETY
(Continued)
ESC Operating Modes

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
system. 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
This mode may be useful if the vehicle becomes
stuck. This mode may modify TCS and ESC
thresholds for activation, which allows for more
wheel spin than normally allowed.
To enter the “Partial Off” mode, momentarily
push the ESC OFF button and the ESC OFF
Indicator Light will illuminate. To turn the ESC
on again, momentarily push the ESC OFF button
and the ESC OFF Indicator Light will turn off.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,
attentive, and skillful driver can prevent acci -
dents. The capabilities of an ESC equipped
vehicle must never be exploited in a reckless or
dangerous manner which could jeopardize the
user’s safety or the safety of others.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 perfor -
mance. Improperly inflated and unevenly worn
tires may also degrade ESC performance.
Any vehicle modification or poor vehicle main -
tenance 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)

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SAFETY277
(Continued)
NOTE:
For vehicles with multiple partial ESC modes,
the push and release of the button will toggle
the ESC modes. Multiple attempts may be
required to return to "ESC On" mode.
Full Off — If Equipped
This mode is intended for off-highway or
off-road use only and should not be used on any
public roadways. In this mode, TCS and ESC
features are turned off. To enter the “Full Off”
mode, push and hold the ESC OFF button for
five seconds while the vehicle is stopped with the engine running. After five seconds, a chime
will sound, the ESC OFF Indicator Light will
illuminate, and the “ESC OFF” message will
display in the instrument cluster. To turn ESC on
again, momentarily push the ESC OFF button.
NOTE:
System may switch from ESC “Full Off” to
“Partial Off” mode when vehicle exceeds a
predetermined speed. When the vehicle speed
slows below the predetermined speed the
system will return to ESC “Full Off”.
ESC modes may also be affected by drive
modes (if equipped).
ESC Activation/Malfunction Indicator Light
And ESC OFF Indicator Light

The ESC Activation/Malfunction Indicator
Light in the instrument cluster will come
on when the ignition is placed in the ON
mode. It should go out with the engine
running. If the ESC Activation/Malfunction Indicator
Light comes on continuously with the engine
running, a malfunction has been detected in the
ESC system. If this 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.

WARNING!

When in “Partial Off” mode, the TCS function -
ality 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.
WARNING!
In the ESC “Full Off” mode, the engine
torque reduction and stability features are
disabled. Therefore, enhanced vehicle
stability offered by the ESC system is
unavailable. In an emergency evasive
maneuver, the ESC system will not engage
to assist in maintaining stability. ESC “Full
Off” mode is intended for off-highway or
off-road use only.
The 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 all
accidents, including those resulting from
excessive speed in turns, driving on very
slippery surfaces, or hydroplaning. ESC also
cannot prevent collisions.
WARNING! (Continued)
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280SAFETY
(Continued)
Hill Start Assist (HSA)
HSA is designed to mitigate roll back from a
complete stop while on an incline. If the driver
releases the brake while stopped on an incline,
HSA will continue to hold the brake pressure for
a short period. If the driver does not apply the
throttle before this time expires, the system will
release brake pressure and the vehicle will roll
down the hill as normal.
The following conditions must be met in order
for HSA to activate:
The feature must be enabled.
The vehicle must be stopped.
The parking brake must be off.
The driver door must be closed.
The vehicle must be on a sufficient grade.
The gear selection must match vehicle uphill
direction (i.e., vehicle facing uphill is in
forward gear; vehicle backing uphill is in
REVERSE gear).

HSA will work in REVERSE gear and all forward
gears. The system will not activate if the trans-
mission is in PARK or NEUTRAL. For vehicles
equipped with a manual transmission, if the
clutch is pressed, HSA will remain active.
Disabling And Enabling HSA
This feature can be turned on or turned off. To
change the current setting, proceed as follows:

If disabling HSA using your instrument cluster
display, see
Ú
page 90 for further information.

If disabling HSA using Uconnect Settings, see
Úpage 228 for further information.
Towing With HSA
HSA will also provide assistance to mitigate roll
back while towing a trailer.
WARNING!

There may be situations where the Hill Start
Assist (HSA) will not activate and slight rolling
may occur, such as on minor hills or with a
loaded vehicle, or while pulling a trailer. HSA is
not a substitute for active driving involvement.
It is always the driver’s responsibility to be
attentive to distance to other vehicles, people,
and objects, and most importantly brake
operation to ensure safe operation of the
vehicle under all road conditions. Your
complete attention is always required while
driving to maintain safe control of your vehicle.
Failure to follow these warnings can result in a
collision or serious personal injury.

WARNING!

If you use a trailer brake controller with your
trailer, the trailer brakes may be activated
and deactivated with the brake switch. If so,
there may not be enough brake pressure to
hold both the vehicle and the trailer on a hill
when the brake pedal is released. In order to
avoid rolling down an incline while resuming
acceleration, manually activate the trailer
brake or apply more vehicle brake pressure
prior to releasing the brake pedal.

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SAFETY281
Traction Control System (TCS)
TCS monitors the amount of wheel spin of each
of the driven wheels. If wheel spin is detected,
the TCS may apply brake pressure to the
spinning wheel(s) and/or reduce engine power
to provide enhanced acceleration and stability.
A feature of the TCS, Brake Limited Differential
(BLD), functions similarly to a limited slip
differential and controls the wheel spin across a
driven axle. If one wheel on a driven axle is
spinning faster than the other, the system will
apply the brake of the spinning wheel. This will
allow more engine power to be applied to the
wheel that is not spinning. BLD may remain
enabled even if TCS and Electronic Stability
Control (ESC) are in reduced modes.
Trailer Sway Control (TSC)
TSC uses sensors in the vehicle to recognize an
excessively swaying trailer and will take the
appropriate actions to attempt to stop the sway.
NOTE:
TSC cannot stop all trailers from swaying.
Always use caution when towing a trailer and
follow the trailer tongue weight recommenda -
tions Ú page 200.
When TSC is functioning, the ESC Activation/
Malfunction Indicator Light will flash, the engine
power may be reduced and you may feel the
brakes being applied to individual wheels to
attempt to stop the trailer from swaying. TSC is
disabled when the ESC system is in the “Partial
Off” or “Full Off” modes.
AUXILIARY DRIVING SYSTEMS
FORWARD COLLISION WARNING (FCW)
W
ITH MITIGATION — IF EQUIPPED
FCW with Mitigation provides the driver with
audible warnings, visual warnings (within the
instrument cluster display), and may apply a
brake jerk to warn the driver when it detects a
potential frontal collision. The warnings and
limited braking are intended to provide the
driver with enough time to react, avoid or
mitigate the potential collision.
NOTE:
FCW monitors the information from the forward
looking sensors as well as the Electronic Brake
Controller (EBC), to calculate the probability of a
forward collision. When the system determines
that a forward collision is probable, the driver
will be provided with audible and visual warn-
ings as well as a possible brake jerk warning.
If the driver does not take action based upon
these progressive warnings, then the system
will provide a limited level of active braking to
help slow the vehicle and mitigate the potential
forward collision. If the driver reacts to the warn -
ings by braking and the system determines that
HSA is not a parking brake. Always apply
the parking brake fully when exiting your
vehicle. Also, be certain to place the trans -
mission in PARK.
Failure to follow these warnings can result
in a collision or serious personal injury.
WARNING! (Continued)
WARNING!
If TSC activates while driving, slow the vehicle
down, stop at the nearest safe location, and
adjust the trailer load to eliminate trailer
sway.
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284SAFETY
TIRE PRESSURE MONITORING
S
YSTEM (TPMS)
(Vehicles Under 10K Gross Vehicle Weight
Rating (GVWR) Only)
The Tire Pressure Monitoring System (TPMS)
will warn the driver of a low tire pressure based
on the vehicle recommended cold placard
pressure.
NOTE:
The TPMS Warning Light will illuminate in the
instrument cluster and a chime will sound when
tire pressure is low in one or more of the four
active road tires. In addition, the instrument
cluster will display a graphic showing the pres -
sure values of each tire with the low tire pres -
sure values in a different color, or the Uconnect
radio will display a TPMS message. When this
occurs you must increase the tire pressure to
the recommended cold placard pressure in
order for the TPMS Warning Light to turn off.
The tire pressure will vary with temperature
by about 1 psi (7 kPa) for every 12°F (6.5°C).
This means that when the outside temperature
decreases, the tire pressure will decrease.
Tire pressure should always be set based on
cold inflation tire pressure. This is defined as the tire pressure after the vehicle has not been
driven for at least three hours, or driven less
than 1 mile (1.6 km) after a three hour period.
The cold tire inflation pressure must not exceed
the maximum inflation pressure molded into
the tire sidewall. The tire pressure will also
increase as the vehicle is driven — this is normal
and there should be no adjustment for this
increased pressure.
See
Úpage 406 on how to properly inflate the
vehicle’s tires.
The TPMS will warn the driver of a low tire
pressure if the tire pressure falls below the
low-pressure warning limit for any reason,
including low temperature effects and natural
pressure loss through the tire.
The TPMS will continue to warn the driver of low
tire pressure as long as the condition exists,
and will not turn off until the tire pressure is
at or above the recommended cold placard
pressure. Once the low TPMS Warning Light
illuminates, you must increase the tire pressure
to the recommended cold placard pressure in
order for the TPMS Warning Light to turn off.
The system will automatically update and the
TPMS Warning Light will turn off once the
system receives the updated tire pressures. The vehicle may need to be driven for up to
20 minutes above 15 mph (24 km/h) in order
for the TPMS to receive this information.
NOTE:
When filling warm tires, the tire pressure may
need to be increased up to an additional 4 psi
(28 kPa) above the recommended cold placard
pressure in order to turn the TPMS Warning
Light off.

For example, your vehicle may have a
recommended cold (parked for more than
three hours) placard pressure of 30 psi
(207 kPa). If the ambient temperature is 68°F
(20°C) and the measured tire pressure is 27 psi
(186 kPa), a temperature drop to 20°F (-7°C) will
decrease the tire pressure to approximately
23 psi (158 kPa). This tire pressure is sufficiently
low enough to turn on the TPMS Warning Light.
Driving the vehicle may cause the tire pressure to
rise to approximately 27 psi (186 kPa), but the
TPMS Warning Light will still be on. In this
situation, the TPMS Warning Light will turn off
only after the tires are inflated to the vehicle’s
recommended cold placard pressure value

Ú

page 449.

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SAFETY285
NOTE:
The TPMS is not intended to replace normal
tire care and maintenance or to provide
warning of a tire failure or condition.
If your vehicle is not equipped with the Tire
Fill Alert feature the TPMS should not be used
as a tire pressure gauge while adjusting your
tire pressure.
Driving on a significantly underinflated tire
causes the tire to overheat and can lead to
tire failure. Underinflation also reduces fuel
efficiency and tire tread life, and may affect
the vehicle’s handling and stopping ability.

The TPMS is not a substitute for proper tire
maintenance, and it is the driver’s responsi -
bility to maintain correct tire pressure using an
accurate tire pressure gauge, even if underin-
flation has not reached the level to trigger illu -
mination of the TPMS Warning Light.

Seasonal temperature changes will affect
tire pressure, and the TPMS will monitor the
actual tire pressure in the tire.
Example: Tire Pressure Monitoring System Display

The Tire Pressure Monitoring System (TPMS)
uses wireless technology with wheel rim
mounted electronic sensors to monitor tire
pressure levels. Sensors, mounted to each
wheel as part of the valve stem, transmit tire
pressure readings to the receiver module.
NOTE:
It is particularly important for you to check the
tire pressure in all of the tires on your vehicle
monthly and to maintain the proper pressure.
CAUTION!
The TPMS has been optimized for the orig -
inal equipment tires and wheels. TPMS
pressures and warning have been estab -
lished for the tire size equipped on your
vehicle. Undesirable system operation or
sensor damage may result when using
replacement equipment that is not of the
same size, type, and/or style. Aftermarket
wheels can cause sensor damage.
Using aftermarket tire sealants may cause
the Tire Pressure Monitoring System
(TPMS) sensor to become inoperable.
After using an aftermarket tire sealant it is
recommended that you take your vehicle to
an authorized dealership to have your
sensor function checked.
After inspecting or adjusting the tire pres -
sure always reinstall the valve stem cap.
This will prevent moisture and dirt from
entering the valve stem, which could
damage the TPMS sensor.
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286SAFETY
The TPMS consists of the following
components:
Receiver module
Four Tire Pressure Monitoring System
sensors
Various Tire Pressure Monitoring System
messages, which display in the instrument
cluster

Tire Pressure Monitoring System Warning Light

Tire Pressure Monitoring System Low
Pressure Warnings
The Tire Pressure Monitoring System
Warning Light will illuminate in the
instrument cluster when tire pressure
is low in one or more of the four active
road tires. The instrument cluster will display a
graphic showing the pressure values of each
tire with the low tire pressure values in a
different color. An "Inflate to XX" message will
also be displayed.
Example: Low Tire Pressure Display

Should this occur, you should stop as soon as
possible and inflate the tires with a low pressure
condition (those in a different color in the
instrument cluster graphic) to the vehicle’s
recommended cold placard pressure inflation
value as shown in the "Inflate to XX" message.
Once the system receives the updated tire
pressures, the system will automatically
update, the graphic display in the instrument
cluster will return to its original color, and the
Tire Pressure Monitoring System Warning Light
will turn off. The vehicle may need to be driven
for up to 20 minutes above 15 mph (24 km/h)
in order for the TPMS to receive this
information. NOTE:
When filling warm tires, the tire pressure may
need to be increased up to an additional 4 psi
(28 kPa) above the recommended cold placard
pressure in order to turn the Tire Pressure Moni
-
toring System Warning Light off.
Service TPMS Warning
If a system fault is detected, the Tire Pressure
Monitoring System Warning Light will flash on
and off for 75 seconds and then remain on
solid. In addition, the instrument cluster will
display a "SERVICE TPM SYSTEM" message for
a minimum of five seconds and then display
dashes (- -) in place of the pressure value to
indicate which sensor is not being received.

If the ignition switch is cycled, this sequence will
repeat, providing the system fault still exists.
If the system fault no longer exists, the Tire
Pressure Monitoring System Warning Light will no
longer flash, and the "SERVICE TPM SYSTEM"
message will no longer display, and a pressure

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