2021 RAM CHASSIS CAB ECU

GETTING TO KNOW YOUR VEHICLE71
3. Lift the front panel until the load floor
unfolds into position.

Load Floor In Open Position

4. Reverse the procedure to store the load floor.
Positioning The Load Floor For Storage Access
Under The Seat

1. Lift the 60/40 seat cushion(s) to the upward position.

2. Unsnap the securing snap located at either side of the load floor.
3. Lift the load floor up to access storage under the load floor.
Load Floor Securing Straps/Crew Cab

4. Reverse the procedure to put the load floor back in the secured down position before
you operate the vehicle.Below Rear Seat Storage (Crew Cab)
The Crew Cab models provide additional
storage under the rear seats. Lift the seats to
access the storage compartment.
To open the storage compartments, unsnap the
securing snap located at either side of the load
floor and lift upward on the fold flat lid.

Crew Cab Storage

NOTE:
For more information on storage and the fold
flat floor, refer to “Fold Flat Load Floor” in the
previous section.WARNING!
Do not drive with the load floor in the up
position. When stopping fast or in an
accident, the load floor could move to the
down position causing serious injury.
2

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104GETTING TO KNOW YOUR INSTRUMENT PANEL

refill the tank when this message is initially
displayed on pickup applications, and approxi-
mately 7 gallons (26 Liters) are required on
chassis-cab applications.
Speed Limited to 5 MPH in XXX mi Refill DEF —
This message will continuously display if the
“DEF Low Refill Soon” message is ignored, and
the frequency of occurrence of the chime will
increase unless up to 2 gallons (7.5 Liters) of
DEF is added to the tank.
5 MPH Max Speed on Restart, Long Idle or
Refuel Refill DEF — This message will continu -
ously display when the counter reaches zero,
and will be accompanied by a periodic chime.

The vehicle will only be capable of a
maximum speed of 5 mph upon the first of
the following conditions to occur:
If the vehicle is shutoff and restarted.

If the vehicle is idled for an extended period
of time, approximately one hour or greater.

If the system detects that the level of fuel
in the tank has increased.

Add a minimum of 2 gallons (7.5 Liters) of DEF
to the tank in order to avoid vehicle operation
at a maximum speed of 5 mph (8 km/h).
NOTE:
A minimum of 2 gallons (7.5 Liters) may be
required to restore normal vehicle operation.
Although the vehicle will start normally and can
be placed in gear after this message has been
initially displayed, extreme caution should be
utilized since the vehicle will only be capable of
maneuvering at a maximum speed of 5 mph
(8 km/h).
Diesel Exhaust Fluid (DEF) Fault Warning
Messages
There are five different messages which are
displayed if the vehicle detects that the DEF
system has been filled with a fluid other than
DEF, has experienced component failures, or
when tampering has been detected. The vehicle
may be limited to a maximum speed of 5 mph
(8 km/h) if the DEF system is not serviced
within less than 200 miles (322 km) of the fault
being detected.
When the DEF system needs to be serviced the
following warnings will display:
Service DEF System See Dealer
— This
message will display when the fault is initially
detected, each time the vehicle is started,
and periodically during driving. The message will be accompanied by a single chime. We
recommend you drive to the nearest autho
-
rized dealer and have your vehicle serviced
as soon as possible.

5 MPH Max Speed in 150 mi Service DEF
System See Dealer — This message will display
if the DEF system has not been serviced after
the “Service DEF System – See Dealer”
message is displayed. This message will
continuously display until the mileage counter
reaches zero, and will be accompanied by a
periodic chime. The message will continue to
countdown until it reaches zero unless the
vehicle is serviced. We recommend you drive
to your nearest authorized dealer and have
your vehicle serviced immediately.

NOTE:
Under some circumstances this mileage
counter may start with a value of less than
150 miles (241 km). For example, if recurring faults are detected in a time interval of less
than 40 hours, the counter may restart at the
value where it stopped when a previous fault
was temporarily remedied, or at a minimum of
50 miles (80 km).

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106GETTING TO KNOW YOUR INSTRUMENT PANEL
NOTE:
The charging system is independent from
load reduction. The charging system
performs a diagnostic on the charging
system continuously.
If the Battery Charge Warning Light is on it
may indicate a problem with the charging
system Úpage 108.
The electrical loads that may be switched off
(if equipped), and vehicle functions which can
be affected by load reduction:
Heated Seats/Vented Seats/Heated Wheel
Rear Defroster And Heated Mirrors
HVAC System
115 Volt AC Power Inverter System
Audio and Telematics System
Loss of the battery charge may indicate one or
more of the following conditions:

The charging system cannot deliver enough
electrical power to the vehicle system because
the electrical loads are larger than the capa -
bility of charging system. The charging system
is still functioning properly.

Turning on all possible vehicle electrical
loads (e.g. HVAC to max settings, exterior
and interior lights, overloaded power outlets
+12 Volts, 115 Volt AC, USB ports) during
certain driving conditions (city driving,
towing, frequent stopping).
Installing options like additional lights,
upfitter electrical accessories, audio
systems, alarms and similar devices.
Unusual driving cycles (short trips separated
by long parking periods).
The vehicle was parked for an extended
period of time (weeks, months).
The battery was recently replaced and was
not charged completely.
The battery was discharged by an electrical
load left on when the vehicle was parked.
The battery was used for an extended period
with the engine not running to supply radio,
lights, chargers, +12 Volt portable appli -
ances like vacuum cleaners, game consoles
and similar devices. What to do when an electrical load reduction
action message is present (“Battery Saver On”
or “Battery Saver Mode”)
During a trip:
Reduce power to unnecessary loads if
possible:

Turn off redundant lights (interior or exterior).

Check what may be plugged in to power
outlets +12 Volts, 115 Volt AC, USB ports.

Check HVAC settings (blower, temperature).

Check the audio settings (volume).
After a trip:
Check if any aftermarket equipment was
installed (additional lights, upfitter electrical
accessories, audio systems, alarms) and
review specifications if any (load and Ignition
Off Draw currents).
Evaluate the latest driving cycles (distance,
driving time and parking time).

The vehicle should have service performed if the
message is still present during consecutive trips
and the evaluation of the vehicle and driving
pattern did not help to identify the cause.

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108GETTING TO KNOW YOUR INSTRUMENT PANEL
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.
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 Ú
page 346.
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.
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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116GETTING 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 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 220.
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.

21_DPF_OM_EN_USC_t.book Page 116

STARTING AND OPERATING131
Your vehicle is equipped with an engine
warm-up protection feature that may limit
engine performance after cold starting at low
ambient temperatures. The length of time
engine speed is limited is dependent upon
engine coolant temperature. Engine speed may
be briefly limited to 1,000 RPM after starting
with coolant temperature below freezing
conditions, and may be limited to 1,000 RPM
for up to approximately two minutes under more
severe cold conditions.
NOTE:
If ambient temperatures are low and the
coolant temperature is below 180°F (82°C),
the engine idle speed will slowly increase to
1,000 RPM after two minutes of idle, if the
following conditions are met:
Foot is off brake pedal and throttle pedal.
Automatic transmission is in PARK.
Vehicle speed is 0 mph (0 km/h).
Applying the throttle will cancel fast idle.
Operating the exhaust brake at idle will
greatly improve warm-up rate and will help
keep the engine close to operating tempera -
ture during extended idle.
ENGINE IDLING
Avoid prolonged idling, long periods of idling
may be harmful to your engine because
combustion chamber temperatures can drop
so low that the fuel may not burn completely.
Incomplete combustion allows carbon and
varnish to form on piston rings, engine valves,
and injector nozzles. Also, the unburned fuel
can enter the crankcase, diluting the oil and
causing rapid wear to the engine.

If the engine is allowed to idle or the truck is
driven on low engine speed drive cycles for more
than two hours, the system will automatically
enter an emissions operating mode that will
increase the engine idle speed to 900 RPM
(1,050 RPM for Chassis Cab). While in this mode,
which is designed to help maintain the Diesel
Particulate Filter, the engine idle speed will return
to normal when the brake pedal is applied.
A small change in engine tone or a slight change
in engine performance while accelerating may
also be noticeable at speeds below 20 mph
(32 km/h). This operating mode may last for up
to an hour of idle time, or around 20 minutes of
driving time. Your truck may have been ordered with an
optional voltage monitoring idle up feature. If a
load is placed on the electrical system while the
truck is in PARK, this feature will attempt to
maintain normal system voltage by automatically
increasing engine idle speed. You may notice
several consecutive increases in idle speed, up to
a maximum of 1,450 RPM, as the system will
attempt to utilize the smallest increase in idle
speed necessary to maintain normal system
voltage. The idle speed will return to normal when
either the electrical load is removed, or when the
brake pedal is applied.

NOTE:
For instrument cluster display messages
related to the vehicle's exhaust system
Ú
page 90.
4

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STARTING AND OPERATING135
Do Not Operate The Engine With Low Oil Pressure
When the engine is at normal operating temperature, the minimum oil pressures required are:
Do Not Operate The Engine With Failed
Parts

All engine failures give some warning before the
parts fail. Be on the alert for changes in
performance, sounds, and visual evidence that the
engine requires service. Some important clues 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.
DIESEL PARTICULATE FILTER (DPF)
M
ANUAL REGENERATION - IF EQUIPPED
On equipped Chassis Cabs, a manual
regeneration can be enable through the
instrument cluster. The manual regeneration
will allow the DPF to complete a regeneration,
lowering the soot level without having to drive
the vehicle. The vehicle must be in PARK to
access this feature, and the fuel level must be
over 12.5% full. A message displaying the time
left on the regeneration will appear on the
instrument cluster, and the instrument cluster
will display the soot level Ú page 90.
ENGINE BLOCK HEATER — IF EQUIPPED
The engine block heater warms the engine, and
permits quicker starts in cold weather. Connect
the cord to a standard 110-115 Volt AC
electrical outlet with a grounded, three-wire
extension cord.
Gas Engine Only
The engine block heater cord is routed through
the grille by the right front tow hook.
It includes a removable cap that is secured by a
tethered strap. It also has a c-clip that is used
for storage when not in use for the Winter
months. During Winter months, remove the
heater cord wiring assembly from itself on the
c-clip.
Idle 700 to 800 RPM
10 psi (69 kPa)
Full speed and load 30 psi (207 kPa)
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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140STARTING AND OPERATING
(Continued)
(Continued)
AUTOMATIC TRANSMISSION
You must press and hold the brake pedal while
shifting out of PARK.
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.
The transmission may not engage PARK if
the vehicle is moving. Always bring the
vehicle to a complete stop before shifting to
PARK, and verify that the transmission gear
position indicator solidly indicates PARK (P)
without blinking. Ensure that the vehicle is
completely stopped, and the PARK position
is properly indicated, before exiting the
vehicle.
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 key fob. When the
ignition is in the LOCK/OFF (key removal)
position, (or, with Keyless Enter-N-Go, when
the ignition is in the OFF mode) the trans -
mission is locked in PARK, securing the
vehicle against unwanted movement.
When leaving the vehicle, always make
sure the ignition is in the OFF mode,
remove the key fob from the vehicle, and
lock the vehicle.
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.
WARNING! (Continued)

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.
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 key fob in or near the
vehicle (or in a location accessible to chil -
dren), and do not leave the ignition (in 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.
WARNING! (Continued)

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