2021 RAM PROMASTER ECU

40GETTING TO KNOW YOUR VEHICLE
WIND BUFFETING
Wind buffeting can be described as the
perception of pressure on the ears or a
helicopter-type sound in the ears. Your vehicle
may exhibit wind buffeting with the windows
down, or the sunroof (if equipped) in certain
open or partially open positions. This is a normal
occurrence and can be minimized. If the
buffeting occurs with the rear windows open,
open the front and rear windows together to
minimize the buffeting. If the buffeting occurs
with the sunroof open, adjust the sunroof
opening to minimize the buffeting or open any
window.
HOOD
OPENING
To open the hood, two latches must be
released.

1. Pull the hood release lever located on the
side of the instrument panel.

Hood Release
2. Move to the outside of the vehicle, reach
into the opening beneath the center of the
hood and push the safety latch lever to the
right to release it, before raising the hood.

Hood Safety Latch Lever Location

3. Raise the hood and place the hood prop rod in hood slot to secure the hood in the open
position.

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GETTING TO KNOW YOUR VEHICLE41

Hood Prop Rod Slot

CLOSINGCARGO AREA FEATURES
The cargo area may be equipped with different
options such as optional side panels, rear seats
and an optional floor.
CAUTION!
Be sure to disengage the rod and secure it in
closed position before closing the hood.
Damage may occur.
WARNING!

Be sure the hood is fully latched before
driving your vehicle. If the hood is not fully
latched, it could open when the vehicle is in
motion and block your vision. Failure to
follow this warning could result in serious
injury or death.

CAUTION!
To prevent possible damage:
Before closing hood, make sure the hood
prop rod is fully seated into its storage
retaining clips.
Do not slam the hood to close it. Use a firm
downward push at the center front edge of
the hood to ensure that both latches
engage. Never drive your vehicle unless the
hood is fully closed, with both latches
engaged.
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50GETTING TO KNOW YOUR INSTRUMENT PANEL
Brake Warning Light, which will turn on when
the brake fluid level in the master cylinder has
dropped below a specified level.
The light will remain on until the cause is
corrected.
NOTE:
The light may flash momentarily during sharp
cornering maneuvers, which change fluid level
conditions. The vehicle should have service
performed, and the brake fluid level checked.
If brake failure is indicated, immediate repair is
necessary.
Vehicles equipped with the Anti-Lock Brake
System (ABS) are also equipped with Electronic
Brake Force Distribution (EBD). In the event of
an EBD failure, the Brake Warning Light will turn
on along with the ABS Light. Immediate repair to
the ABS system is required. Operation of the Brake Warning Light can be
checked by turning the ignition switch from the
OFF position to the ON/RUN position. The light
should illuminate for approximately two
seconds. The light should then turn off unless
the parking brake is applied or a brake fault is
detected. If the light does not illuminate, have
the light inspected by an authorized dealer.
The light also will turn on when the parking
brake is applied with the ignition switch in the
ON/RUN position.
NOTE:
This light shows only that the parking brake is
applied. It does not show the degree of brake
application.
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.
Vehicle Security Warning Light — If
Equipped
This light will flash at a fast rate for
approximately 15 seconds when the
vehicle security system is arming, and
then will flash slowly until the vehicle
is disarmed.
YELLOW WARNING LIGHTS
Immobilizer Fail / VPS Electrical Alarm
Indicator Light
This telltale will illuminate when the
vehicle security system system has
detected an attempt to break into the
vehicle.
NOTE:
After cycling the ignition to the ON/RUN posi -
tion, the Vehicle Security Warning Light could
illuminate if a problem with the system is
detected. This condition will result in the engine
being shut off after two seconds.
WARNING!
Driving a vehicle with the red brake light on is
dangerous. Part of the brake system may
have failed. It will take longer to stop the
vehicle. You could have a collision. Have the
vehicle checked immediately.

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GETTING TO KNOW YOUR INSTRUMENT PANEL55
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 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 88
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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60STARTING AND OPERATING
(Continued)
AUTOMATIC TRANSMISSION
You must press and hold the brake pedal while
shifting out of PARK.
KEY IGNITION PARK INTERLOCK
This vehicle is equipped with a Key Ignition Park
Interlock which requires the transmission to be
in PARK before the ignition can be turned to the
LOCK/OFF (key removal) position. The key can
only be removed from the ignition when the
ignition is in the LOCK/OFF position, and once
removed the transmission is locked in PARK.
NOTE:
If a malfunction occurs, the system will trap the
key in the ignition to warn you that this safety
feature is inoperable. The engine can be started
and stopped but the key cannot be removed
until you obtain service.
BRAKE/TRANSMISSION SHIFT
I
NTERLOCK SYSTEM
This vehicle is equipped with a Brake
Transmission Shift Interlock System (BTSI) that
holds the transmission gear selector in PARK
unless the brakes are applied. To shift the
transmission out of PARK, the ignition must be
turned to the ON/RUN mode (engine running or
not), and the brake pedal must be pressed.
WARNING!
It is dangerous to shift out of PARK or
NEUTRAL if the engine speed is higher than
idle speed. If your foot is not firmly pressing
the brake pedal, the vehicle could accel -
erate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and your
foot is firmly pressing the brake pedal.
Unintended movement of a vehicle could
injure those in or near the vehicle. As with
all vehicles, you should never exit a vehicle
while the engine is running. Before exiting a
vehicle always come to a complete stop,
then apply the parking brake, shift the
transmission into PARK, turn the engine
OFF, and remove the ignition key. Once the
key is removed, the transmission is locked
in PARK, securing the vehicle against
unwanted movement.
When leaving the vehicle, always remove
the ignition key from the vehicle and lock
the vehicle.

Never leave children alone in a vehicle, or
with access to an unlocked vehicle. Allowing
children to be in a vehicle unattended is
dangerous for a number of reasons. A child
or others could be seriously or fatally injured.
Children should be warned not to touch the
parking brake, brake pedal or the transmis -
sion gear selector.
Do not leave the ignition key in or near the
vehicle (or in a location accessible to chil -
dren). A child could operate power windows,
other controls, or move the vehicle.

CAUTION!

Shift into or out of PARK or REVERSE only
after the vehicle has come to a complete stop.

Do not shift between PARK, REVERSE,
NEUTRAL, or DRIVE when the engine is
above idle speed.
Before shifting into any gear, make sure
your foot is firmly pressing the brake pedal.
WARNING! (Continued)

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62STARTING AND OPERATING
(Continued)
(Continued)
Gear Ranges
Do not press the accelerator pedal when
shifting out of PARK or NEUTRAL.
NOTE:
After selecting any gear range, wait a moment
to allow the selected gear to engage before
accelerating. This is especially important when
the engine is cold.
PARK (P)
This range supplements the parking brake by
locking the transmission. The engine can be
started in this range. Never attempt to use
PARK while the vehicle is in motion. Apply the
parking brake when exiting the vehicle in this
range.
When parking on a hill, apply the parking brake
before shifting the transmission to PARK,
otherwise the load on the transmission locking
mechanism may make it difficult to move the
gear selector out of PARK. As an added
precaution, turn the front wheels toward the
curb on a downhill grade, and away from the
curb on an uphill grade. When exiting the vehicle, always:Apply the parking brake.
Shift the transmission into PARK.
Turn the engine off.
Remove the ignition key.
WARNING!
Never use the PARK position as a substi
-
tute for the parking brake. Always apply the
parking brake fully when exiting the vehicle
to guard against vehicle movement and
possible injury or damage.
Your vehicle could move and injure you and
others if it is not in PARK. Check by trying to
move the gear selector out of PARK with the
brake pedal released. Make sure the trans -
mission is in PARK before exiting the
vehicle.
It is dangerous to shift out of PARK or
NEUTRAL if the engine speed is higher than
idle speed. If your foot is not firmly pressing
the brake pedal, the vehicle could accel -
erate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and your
foot is firmly pressing the brake pedal.
Unintended movement of a vehicle could
injure those in or near the vehicle. As with
all vehicles, you should never exit a vehicle
while the engine is running. Before exiting a
vehicle always come to a complete stop,
then apply the parking brake, shift the
transmission into PARK, turn the engine off,
and remove the ignition key. Once the key is
removed, the transmission is locked in
PARK, securing the vehicle against
unwanted movement.
WARNING! (Continued)

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STARTING AND OPERATING77
TIRE SIZE
The tire size on the Vehicle Certification Label
represents the actual tire size on your vehicle.
Replacement tires must be equal to the load
capacity of this tire size.
RIM SIZE
This is the rim size that is appropriate for the tire
size listed.
INFLATION PRESSURE
This is the cold tire inflation pressure for your
vehicle for all loading conditions up to full Gross
Axle Weight Rating (GAWR).
CURB WEIGHT
The curb weight of a vehicle is defined as the
total weight of the vehicle with all fluids,
including vehicle fuel, at full capacity
conditions, and with no occupants or cargo
loaded into the vehicle. The front and rear curb
weight values are determined by weighing your
vehicle on a commercial scale before any
occupants or cargo are added.
OVERLOADING
The load carrying components (axle, springs,
tires, wheels, etc.) of your vehicle will provide
satisfactory service as long as you do not
exceed the Gross Vehicle Weight Rating (GVWR)
and the front and rear Gross Axle Weight Rating
(GAWR).
The best way to figure out the total weight of
your vehicle is to weigh it when it is fully loaded
and ready for operation. Weigh it on a
commercial scale to ensure that it is not over
the GVWR.
Figure out the weight on the front and rear axle
of the vehicle separately. It is important that you
distribute the load evenly over the front and rear
axles.
Overloading can cause potential safety hazards
and shorten useful service life. Heavier axles or
suspension components do not necessarily
increase the vehicle's GVWR.
LOADING
To load your vehicle properly, first figure out its
empty weight, axle-by-axle and side-by-side.
Store heavier items down low and be sure you
distribute their weight as evenly as possible.
Stow all loose items securely before driving. If
weighing the loaded vehicle shows that you
have exceeded either Gross Axle Weight Rating
(GAWR), but the total load is within the specified
Gross Vehicle Weight Rating (GVWR), you must
redistribute the weight. Improper weight
distribution can have an adverse effect on the
way your vehicle steers and handles and the
way the brakes operate.
NOTE:
Refer to the “Vehicle Certification Label” affixed
to the rear of the driver's door for your vehicle's
GVWR and GAWRs.
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82STARTING AND OPERATING
(Continued)
Towing Requirements — Tires
Do not attempt to tow a trailer while using a
compact spare tire.
Do not drive more than 50 mph (80 km/h) when towing while using a full size spare tire.
Proper tire inflation pressures are essential
to the safe and satisfactory operation of your
vehicle.
Check the trailer tires for proper tire inflation
pressures before trailer usage.
Check for signs of tire wear or visible tire
damage before towing a trailer.
Replacing tires with a higher load carrying
capacity will not increase the vehicle's GVWR
and GAWR limits.
For further information Ú page 240.
Towing Requirements — Trailer Brakes
Do not interconnect the hydraulic brake
system or vacuum system of your vehicle
with that of the trailer. This could cause inad -
equate braking and possible personal injury.
WARNING!
Make certain that the load is secured in the
trailer and will not shift during travel. When
trailering cargo that is not fully secured,
dynamic load shifts can occur that may be
difficult for the driver to control. You could
lose control of your vehicle and have a
collision.
When hauling cargo or towing a trailer, do
not overload your vehicle or trailer. Over -
loading can cause a loss of control, poor
performance or damage to brakes, axle,
engine, transmission, steering, suspension,
chassis structure or tires.
Safety chains must always be used
between your vehicle and trailer. Always
connect the chains to the hook retainers of
the vehicle hitch. Cross the chains under
the trailer tongue and allow enough slack
for turning corners.
Vehicles with trailers should not be parked
on a grade. When parking, apply the
parking brake on the tow vehicle. Put the
tow vehicle transmission in PARK. For
four-wheel drive vehicles, make sure the
transfer case is not in NEUTRAL. Always,
block or "chock" the trailer wheels.
GCWR must not be exceeded.
Total weight must be distributed between
the tow vehicle and the trailer such that the
following four ratings are not exceeded :
GVWR
GTW
GAWR
Tongue weight rating for the trailer
hitch utilized.
WARNING! (Continued)

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