2020 Ram 1500 AC system

If your OBD II system is not ready, you should see an autho -
rized 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 oper
-
ation 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.
3
2020_DT_1500_OM_US.book Page 197
GETTING TO KNOW YOUR INSTRUMENT PANEL 197

198
(Continued)
SAFETY
SAFETY FEATURES
Anti-Lock Brake System (ABS)
The Anti-Lock Brake System (ABS) provides increased
vehicle stability and brake performance under most braking
conditions. The system automatically prevents wheel lock,
and enhances vehicle control during braking.
The ABS performs a self-check cycle to ensure that the ABS
is working properly each time the vehicle is started and
driven. During this self-check, you may hear a slight clicking
sound as well as some related motor noises.
ABS is activated during braking when the system detects one
or more wheels begin to lock. Road conditions such as ice,
snow, gravel, bumps, railroad tracks, loose debris, or panic
stops may increase the likelihood of ABS activation(s).
You also may experience the following when ABS activates:
• The ABS motor noise (it may continue to run for a shorttime after the stop)
• The clicking sound of solenoid valves • Brake pedal pulsations
• A slight drop of the brake pedal at the end of the stop
These are all normal characteristics of ABS.
WARNING!
• The ABS contains sophisticated electronic equipment that may be susceptible to interference caused by
improperly installed or high output radio transmitting
equipment. This interference can cause possible loss of
anti-lock braking capability. Installation of such equip -
ment should be performed by qualified professionals.
• Pumping of the Anti-Lock Brakes will diminish their effectiveness and may lead to a collision. Pumping
makes the stopping distance longer. Just press firmly
on your brake pedal when you need to slow down or
stop.
2020_DT_1500_OM_US.book Page 198

SAFETY 199
ABS is designed to function with the Original Equipment
Manufacturer (OEM) tires. Modification may result in
degraded ABS performance.
Anti-Lock Brake Warning Light
The yellow “Anti-Lock Brake Warning Light” will turn on
when the ignition is turned to the ON/RUN mode and may
stay on for as long as four seconds.If the “Anti-Lock Brake Warning Light” remains on or comes
on while driving, it indicates that the anti-lock portion of the
brake system is not functioning and that service is required.
However, the conventional brake system will continue to
operate normally if the “Anti-Lock Brake Warning Light” is
on.
If the “Anti-Lock Brake Warning Light” is on, the brake
system should be serviced as soon as possible to restore the
benefits of anti-lock brakes. If the “Anti-Lock Brake Warning
Light” does not come on when the ignition is turned to the
ON/RUN mode, have the light repaired as soon as possible.
Electronic Brake Control System
Your vehicle is equipped with an advanced Electronic Brake
Control (EBC) system. This system includes Electronic Brake
Force Distribution (EBD), Anti-Lock Brake System (ABS),
Brake Assist System (BAS), Hill Start Assist (HSA), Traction
Control System (TCS), Electronic Stability Control (ESC),
and Electronic Roll Mitigation (ERM). These systems work
together to enhance both vehicle stability and control in
various driving conditions.
Your vehicle may also be equipped with Trailer Sway
Control (TSC) and Hill Descent Control (HDC).
• The ABS cannot prevent the natural laws of physics
from acting on the vehicle, nor can it increase braking
or steering efficiency beyond that afforded by the
condition of the vehicle brakes and tires or the traction
afforded.
• The ABS cannot prevent collisions, including those resulting from excessive speed in turns, following
another vehicle too closely, or hydroplaning.
• The capabilities of an ABS equipped vehicle must never be exploited in a reckless or dangerous manner
that could jeopardize the user’s safety or the safety of
others.
WARNING! (Continued)
4
2020_DT_1500_OM_US.book Page 199

200 SAFETY
Brake Assist System (BAS)
The Brake Assist System (BAS) is designed to optimize the
vehicle’s braking capability during emergency braking
maneuvers. The system detects an emergency braking situa-
tion by sensing the rate and amount of brake application, and
then applies optimum pressure to the brakes. This can help
reduce braking distances. The BAS complements the
Anti-lock Brake System (ABS). Applying the brakes very
quickly results in the best BAS assistance. To receive the
benefit of the system, you must apply continuous braking
pressure during the stopping sequence, (do not “pump” the
brakes). Do not reduce brake pedal pressure unless braking
is no longer desired. Once the brake pedal is released, the
BAS is deactivated. Brake System Warning Light
The red “Brake System Warning Light” will turn on when
the ignition is turned to the ON/RUN mode and may stay on
for as long as four seconds.
If the “Brake System Warning Light” remains on or comes on
while driving, it indicates that the brake system is not func
-
tioning properly and that immediate service is required. If
the “Brake System Warning Light” does not come on when
the ignition is turned to 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 ABS before the front axle.
Electronic Roll Mitigation (ERM)
The Electronic Roll Mitigation (ERM) system anticipates the
potential for wheel lift by monitoring the driver’s steering
wheel input and the speed of the vehicle. When ERM deter -
mines that the rate of change of the steering wheel angle and
vehicle’s speed are sufficient to potentially cause wheel lift,
WARNING!
The Brake Assist System (BAS) cannot prevent the
natural laws of physics from acting on the vehicle, nor
can it increase the traction afforded by prevailing road
conditions. BAS cannot prevent collisions, including
those resulting from excessive speed in turns, driving on
very slippery surfaces, or hydroplaning. The capabilities
of a BAS-equipped vehicle must never be exploited in a
reckless or dangerous manner, which could jeopardize
the user's safety or the safety of others.
2020_DT_1500_OM_US.book Page 200

SAFETY 201
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 condi-
tions, leaving the roadway, or striking objects or other vehi -
cles.
NOTE:
ERM is disabled anytime the ESC is in “Full Off” mode (if
equipped). Refer to “Electronic Stability Control (ESC)” in
this section for a complete explanation of the available ESC
modes. Electronic Stability Control (ESC)
The Electronic Stability Control (ESC) system enhances
directional control and stability of the vehicle under various
driving conditions. ESC corrects for oversteering or under
-
steering of the vehicle by applying the brake of the appro -
priate 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 appro -
priate for the steering wheel position.
• Understeer — when the vehicle is turning less than appro -
priate 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
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.
4
2020_DT_1500_OM_US.book Page 201

202 SAFETY
(Continued)
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 condi -
tions. Only a safe, attentive, and skillful driver can
prevent accidents. 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 perfor -
mance 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 effective -
ness of the ESC system can increase the risk of loss of
vehicle control, vehicle rollover, personal injury and
death.
WARNING! (Continued)
2020_DT_1500_OM_US.book Page 202

SAFETY 203
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. Alter-
nate 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 illumi -
nate. 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 pushed may be required to return to ESC On.
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” switch for five
seconds while the vehicle is stopped with the engine
running. After five seconds, a chime will sound, the “ESC Off
WARNING!
• When in “Partial Off” mode, the TCS functionality 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.
4
2020_DT_1500_OM_US.book Page 203

204 SAFETY
(Continued)
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” switch.
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 so
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 igni -
tion is placed in the ON/RUN 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 (kilome -
ters) at speeds greater than 30 mph (48 km/h), see an autho -
rized dealer as soon as possible to have the problem
diagnosed and corrected.
WARNING!
• In the ESC “Full Off” mode, the engine torque reduc -
tion 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 hydro -
planing. ESC also cannot prevent collisions.
WARNING! (Continued)
2020_DT_1500_OM_US.book Page 204