ECO mode FORD SUPER DUTY 2021 Repair Manual

To return to the normal drive (D) position,
move the shift lever from manual (M) to
drive (D).
The transmission operates through the full
range of gears.
Forced downshifts
•
Allowed in drive (D) with the tow/haul
feature on or off.
• Press the accelerator to the floor.
• Allows transmission to select an
appropriate gear.
Understanding Your SelectShift
Automatic ™ TransmissionNote:
When pressing the button on the
gearshift lever, you can cycle through the
available drive modes. See Drive Control
(page 268).
Your vehicle has a SelectShift Automatic ™
transmission gearshift lever. The
SelectShift Automatic transmission gives
you the ability to change gears up or down
without a clutch. To prevent the engine from running at too
low an RPM, which may cause it to stall,
SelectShift still makes some downshifts
for you if it determines that you have not
downshifted in time. Although SelectShift
makes some downshifts for you, it still
allows you to downshift at any time if the
SelectShift determines that damage to
the engine cannot occur from over-revving.
SelectShift does not upshift, even if the
engine is approaching the RPM limit. Shift
it manually by pressing the + button.
Note:
Engine damage could occur if you
maintain excessive engine revving without
shifting.
The SelectShift Automatic transmission
feature has two modes:
• Progressive Range Selection.
• Manual (M).
Progressive Range Selection - PRS Progressive Range Selection gives you the
ability to lockout gears from the automatic
shifting range. This could provide you with
an improved driving experience, for
example, in slippery conditions or when
experiencing a steep slope.
With the gearshift lever in drive (D), press
the – button to active PRS. The instrument
cluster indicates the available and selected
gears.
208
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing TransmissionE249567 E312894

USING FOUR-WHEEL DRIVE
Note:
For important information regarding
the safe operation of this type of vehicle,
see General Information in the Wheels and
Tires chapter.
Note: Do not use 4H or 4L mode on dry,
hard surfaced roads. Doing so can produce
excessive noise, increase tire wear and may
damage drive components. 4X4 mode is
only intended for consistently slippery or
loose surfaces. Use of 4L mode on these
surfaces may produce some noise, such as
occasional clunks, but will not damage drive
components.
Note: If 4X4 low is selected while the
vehicle is moving above 3 mph (5 km/h),
the 4WD system will not perform a shift.
This is normal and should be no reason for
concern. Refer to Shifting to or from 4L (4X4
Low) for proper operation.
Note: You can switch on and switch off the
electronic locking differential by pulling the
4WD control (4WD vehicles) or turning the
electronic locking differential control (2WD
vehicles). See
Electronic Locking
Differential (page 221).
Electronic Shift-On-the-Fly
(ESOF) 4WD system
(If Equipped)
Note: If 4X4 Low is selected while the
vehicle is moving above
3 mph (5 km/h),
the 4WD system will not perform a shift.
This is normal and should be no reason for
concern. Refer to Shifting to or from 4L (4X4
Low) for proper system operation.
Note: Auto-manual hub locks can be
manually locked by rotating the hub lock
control from AUTO to LOCK. For proper operation, make sure that each
hub is fully engaged and that both hub
locks are set to the same position (both
set to LOCK or both set to AUTO). To
engage LOCK, turn the hub locks
completely clockwise; to engage AUTO,
turn the hub locks completely
counterclockwise.
The ESOF 4WD system:
•
Provides 4x4 High engagement and
disengagement while the vehicle is
moving.
• Is operated by a rotary control located
on the instrument panel that allows
you select 4x2, 4x4 High or 4x4 Low
operation.
• Uses auto-manual hub locks that can
be engaged and disengaged
automatically based on the 4x4 mode
selected.
• Will increase fuel economy when used
in the hub lock's recommended AUTO
mode.
4WD Indicator Lights
Note: When a 4X4 system fault is present,
the system will typically remain in whichever
4X4 mode was selected prior to the fault
condition occurring. It will not default to 4X2
in all circumstances. When this warning is
displayed, have your vehicle serviced by an
authorized dealer.
213
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Four-Wheel Drive
(If Equipped)LOC K
OTUAE339076

4X2
Momentarily illuminates when
2H is selected.
4X4 HIGH Continuously illuminates when
4H is selected.
4X4 LOW Continuously illuminates when
4L is selected.
CHECK 4X4 Displays when a 4X4 fault is
present.
Using the Electronic Shift on the
Fly 4WD system (If Equipped) 2H (4X2)
For general on-road driving. Sends power
to the rear wheels only and should be used
for street and highway driving. Provides
optimal smoothness and fuel economy at
high speeds. 4H (4X4 HIGH)
Provides mechanically locked four-wheel
drive power to both the front and rear
wheels for use in off-road or winter
conditions such as deep snow, sand or
mud. This mode is not for use on dry
pavement.
4L (4X4 LOW)
Provides mechanically locked four-wheel
drive power to both the front and rear
wheels for use on low traction surfaces,
but does so with additional gearing for
increased torque multiplication. Intended
only for off-road applications such as deep
sand, steep grades, or pulling heavy
objects. 4L (4X4 low) will not engage while
your vehicle is moving above
3 mph
(5 km/h); this is normal and should be no
reason for concern. Refer to Shifting to or
from 4L (4X4 low) for proper operation.
Shifting Between System Modes
Note: Momentarily releasing the accelerator
pedal when a shift in progress message
displays improves engagement or
disengagement performance.
Note: Do not perform this operation if the
rear wheels are slipping or when applying
the accelerator pedal.
Note: Some noise may be heard as the
system shifts or engages; this is normal.
Note: 4X4 high mode is not intended for
use on dry pavement.
You can move the control from 2H or 4H
at a stop or while driving. The information
display may display a message indicating
a 4X4 shift is in progress. Once the shift is
complete the message center will then
display the system mode selected.
Shifting to or from 4L (4X4 low)
Note: Some noise may be heard as the
system shifts or engages; this is normal.
214
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Four-Wheel Drive
(If Equipped)E181778 E181779 E181780 E191851

Note:
4x4 low mode is not intended for use
on dry pavement.
1. Bring the vehicle to a speed of 3 mph
(5 km/h) or less.
2. Place the transmission in neutral (N).
3. Move the 4WD control to the preferred
position.
The information display will display a
message indicating a 4X4 shift is in
progress. The information display will then
display the system mode selected. If any
of the above shift conditions are not met,
the shift will not occur and the information
display will display information guiding the
driver through the proper shifting
procedures.
If a message in the information display
shows a Shift Delayed Pull Forward
message, a transfer case gear tooth
blockage is present. To alleviate this
condition, place the transmission in a
forward gear, move the vehicle forward
approximately
5 ft (1.5 m), and shift the
transmission back to neutral to allow the
transfer case to complete the range shift.
Entering and Exiting Rock Crawl
Mode with Tremor Package
(If
Equipped) •
To enter rock crawl, your vehicle must
be in 4x4 low.
• Press the drive mode button on the
shifter column to bring up the
information display and select rock
crawl mode.
• With the switch in 4x4 low position,
press rock crawl mode again to
deactivate it. •
You can now perform a shift out of 4x4
low.
• Refer to Shifting to or from 4L (4x4
low) as described previously for proper
operation of 4x4 low in this procedure.
Operating 4WD Vehicles with
Spare or Mismatched Tires
On four-wheel drive vehicles, the size of
the spare tire can affect the 4X4 system.
If there is a significant difference between
the size of the spare tire and the remaining
tires, you may have limited four-wheel
drive functionality.
When driving with the full-size, dissimilar
spare wheel and tire assembly, we
recommend that you do not:
• Exceed
50 mph (80 km/h) with a 4WD
mode turned on.
• Turn on a 4WD mode unless the
vehicle is stationary.
• Use a 4WD mode on dry pavement.
When driving with the full-size, dissimilar
spare wheel and tire assembly, you may
have limited 4WD functionality, especially
when driving in a mechanically locked 4WD
mode. You may experience the following:
• Additional noise from the transfer case
or other drive components.
• Difficulty shifting out of a mechanically
locked 4WD mode.
Use of a dissimilar spare wheel and tire
assembly may lead to impairment of the
following:
• Comfort and noise.
• Winter weather driving capability.
• Wet driving capability.
• Four-wheel drive capability.
215
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Four-Wheel Drive
(If Equipped)E225315

How Your Vehicle Differs from
Other Vehicles
WARNING: Vehicles with a higher
center of gravity (utility and four-wheel
drive vehicles) handle differently than
vehicles with a lower center of gravity
(passenger cars). Avoid sharp turns,
excessive speed and abrupt steering in
these vehicles. Failure to drive cautiously
increases the risk of losing control of your
vehicle, vehicle rollover, personal injury
and death.
Truck and utility vehicles can differ from
some other vehicles. Your vehicle may be
higher to allow it to travel over rough
terrain without getting hung up or
damaging underbody components.
The differences that make your vehicle so
versatile also make it handle differently
than an ordinary passenger car.
Maintain steering wheel control at all
times, especially in rough terrain. Since
sudden changes in terrain can result in
abrupt steering wheel motion, make sure
you grip the steering wheel from the
outside. Do not grip the spokes.
Drive cautiously to avoid vehicle damage
from concealed objects such as rocks and
stumps.
You should either know the terrain or
examine maps of the area before driving.
Map out your route before driving in the
area. To maintain steering and braking
control of your vehicle, you must have all
four wheels on the ground and they must
be rolling, not sliding or spinning. Driving Off-Road With Truck and
Utility Vehicles
Note:
On some models, the initial shift from
two-wheel drive to four-wheel drive while
the vehicle is moving can cause some
momentary clunk and ratcheting sounds.
This is the front drivetrain coming up to
speed and the automatic locking hubs
engaging and is not cause for concern.
Note: Your vehicle may come with a front
air dam that can become damaged (due to
reduced ground clearance) when taking your
vehicle off-road. This air dam can be taken
off by removing 15 bolts.
Four-wheel drive vehicles are specially
equipped for driving on sand, snow, mud
and rough terrain and have operating
characteristics that are somewhat
different from conventional vehicles, both
on and off the road.
Power is supplied to all four wheels
through a transfer case. On four-wheel
drive vehicles, the transfer case allows you
to select 4WD when necessary.
Information on transfer case operation and
shifting procedures can be found in this
chapter. Information on transfer case
maintenance can be found in the
Maintenance chapter. You should become
thoroughly familiar with this information
before you operate your vehicle.
Four-wheel drive (when you select a 4WD
mode) uses all four wheels to power the
vehicle. This increases traction, enabling
you to drive over terrain and road
conditions that a conventional two-wheel
drive vehicle cannot.
216
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Four-Wheel Drive
(If Equipped)

Basic Operating Principles
•
Drive slower in strong crosswinds which
can affect the normal steering
characteristics of your vehicle.
• When driving your vehicle on surfaces
made slippery by loose sand, water,
gravel, snow or ice proceed with care.
• Do not use 4H or 4L on dry, hard
surfaced roads. Doing so will produce
excessive noise, increase tire wear and
may damage drive components. 4H or
4L modes are only intended for
consistently slippery or loose surfaces.
If Your Vehicle Leaves the Road
If your vehicle leaves the road, reduce your
vehicle speed and avoid severe braking.
When your vehicle speed has been
reduced, ease your vehicle back onto the
road. Do not turn the steering wheel
sharply while returning your vehicle to the
road.
It may be safer to stay on the shoulder of
the road and slow down gradually before
returning to the road. You may lose control
if you do not slow down or if you turn the
steering wheel too sharply or abruptly.
It may be less risky to strike small objects,
such as freeway reflectors, with minor
damage to your vehicle rather than
attempt a sudden return to the road which
could cause your vehicle to slide sideways
out of control or roll over. Remember, your
safety and the safety of others should be
your primary concern.
Emergency Maneuvers
In an unavoidable emergency situation
where a sudden sharp turn must be made,
remember to avoid over-driving your
vehicle (i.e. turn the steering wheel only as
rapidly and as far as required to avoid the
emergency). Excessive steering can result
in loss of vehicle control. Apply smooth
pressure to the accelerator pedal or brake pedal when changes in vehicle speed are
required. Avoid abrupt steering,
acceleration and braking. This could result
in an increased risk of vehicle roll over, loss
of vehicle control and personal injury. Use
all available road surface to bring your
vehicle to a safe direction of travel.
In the event of an emergency stop, avoid
skidding the tires and do not attempt any
sharp steering wheel movements.
If your vehicle goes from one type of
surface to another (i.e. from concrete to
gravel) there will be a change in the way
your vehicle responds to a maneuver (i.e.
steering, acceleration or braking).
Sand
When driving over sand, try to keep all four
wheels on the most solid area of the trail.
Avoid reducing the tire pressures but shift
to a lower gear and drive steadily through
the terrain. Apply the accelerator slowly
and avoid excessive wheel slip.
When driving at slow speeds in deep sand
under high outside temperatures, use a low
gear when possible. Low gear operation
will maximize the engine and transmission
cooling capability.
Avoid driving at excessive speeds, this
causes vehicle momentum to work against
you and your vehicle could become stuck
to the point that assistance may be
required from another vehicle. Remember,
you may be able to back out the way you
came if you proceed with caution.
Mud and Water
Mud
Be cautious of sudden changes in vehicle
speed or direction when you are driving in
mud. Even four-wheel drive vehicles can
lose traction in slick mud. If your vehicle
does slide, steer in the direction of the slide
until you regain control of your vehicle.
217
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Four-Wheel Drive (If Equipped)

LIMITED SLIP DIFFERENTIAL
(IF EQUIPPED)
This axle provides added traction on
slippery surfaces, particularly when one
wheel is on a poor traction surface. Under
normal conditions, the limited-slip axle
functions like a standard rear axle. The axle
may exhibit a slight noise or vibration
during tight turns with low vehicle speed.
This is normal behavior and indicates the
axle is working.
ELECTRONIC LOCKING
DIFFERENTIAL (IF EQUIPPED)
Note: The electronic locking differential is
for off-road use only and is not for use on
dry pavement. Using the electronic locking
differential on dry pavement will result in
increased tire wear, noise and vibration.
The electronic locking differential is a
device housed in the rear axle that allows
both rear wheels to turn at the same
speed. The electronic locking differential
can provide additional traction should your
vehicle become stuck. You can activate
the differential electronically and shift it
on the fly within the differential operating
speed range. The differential is for use in
mud, rocks, sand, or any off-road condition
where you need maximum traction. It is
not for use on dry pavement.
The following conditions will affect the
electronic locking differential:
• The electronic locking differential will
not engage if your vehicle speed is
above 20 mph (32 km/h) in 4x2, or 4x4
High modes.
• The electronic locking differential will
not engage if your vehicle speed is
above or
56 mph (90 km/h) in 4X4
Low. •
The electronic locking differential may
not engage if you press your
accelerator pedal during an
engagement attempt. A message may
display in the instrument display
guiding you to release the accelerator
pedal.
• In 4x2, and 4x4 High modes, the
electronic locking differential will
automatically disengage at speeds
above
25 mph (41 km/h) and will
automatically reengage at speeds
below
20 mph (32 km/h).
• In 4L (4X4 low), the electronic locking
differential will automatically
disengage at speeds above
62 mph
(100 km/h) and will automatically
reengage at speeds below 56 mph
(90 km/h).
• The AdvanceTrac system has the
ability to take over control of the
electronic locking differential and
disable it during driving maneuvers
when necessary.
When you switch the system on, if you do
not meet the required conditions for
electronic locking differential activation,
the instrument cluster will display the
appropriate information guiding you
through the proper activation process.
Activating the Electronic Locking
Differential
Note: Do not use electronic locking
differential on dry, hard surfaced roads.
Doing so will produce excessive noise,
vibration and increase tire wear.
Note: If the electronic locking differential
has difficulty disengaging, release the
accelerator pedal and turn the steering
wheel in the opposite direction while rolling.
221
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Rear Axle

This feature increases engine braking at
higher engine speeds to provide better
grade descent control with less brake and
transmission wear and tear.
Note:
Use this when driving downhill and
carrying heavy loads or trailering.
Benefits of engine braking are:
• Lower brake temperature.
• Reduced brake fade.
• Longer brake life.
• Improved driving and trailering control. Press the button on the switch
bank next to the audio unit to
switch the system on or off.
There are two engine brake modes, manual
and automatic.
Manual Engine Braking
1. Press the button to switch on manual engine braking.
2. Release the accelerator pedal to maximize engine braking.
3. Apply the brakes. The transmission downshifts to lower gears.
Note: The engine braking feature only
functions when you release the accelerator.
Note: You can shift the transmission to
lower gears with progressive range selection
(PRS) or manual shifting independent of
pressing the brakes.
Note: You can also use manual engine
braking with cruise control to improve grade
descent control.
Note: If your vehicle has Adaptive Cruise
Control, the speed control system uses the
selected engine brake mode, transmission
gears, and brakes to maintain the set speed
and distance to the vehicle being followed. Automatic Engine Braking
1. Press the button twice to switch on
automatic engine braking.
2. Release the accelerator or brake pedal.
The system remembers your vehicle
speed.
Note: This feature offers smoother, less
aggressive engine braking during downhill
descents. It may not apply braking if the
vehicle speed is not increasing, although it
will apply full engine braking force when
needed to prevent acceleration. The system
automatically activates the engine brake
and, if necessary, downshifts the
transmission to lower gears to not exceed
your vehicle's set speed when the brake or
accelerator were last released.
Warning Lamp Conditions
• Illuminates when this feature is
switched on and the system is
operating properly. See Warning
Lamps and Indicators (page 105).
• Flashes when the engine brake is
disabled due to a fault or the engine
does not meet the required braking
conditions.
• Does not illuminate when the switch
or indicator is faulty.
You can switch the system on at anytime.
The system becomes active once the
braking conditions are met.
Braking Conditions
• Your vehicle is in a forward gear.
• The engine speed is above about 1500
RPM.
• Your foot is off the accelerator.
224
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing BrakesE171217

PRINCIPLE OF OPERATION
The traction control system helps avoid
drive wheel spin and loss of traction.
If your vehicle begins to slide, the system
applies the brakes to individual wheels
and, when needed, reduces engine power
at the same time. If the wheels spin when
accelerating on slippery or loose surfaces,
the system reduces engine power in order
to increase traction.
USING TRACTION CONTROL
WARNING: The stability and
traction control light illuminates steadily
if the system detects a failure. Make sure
you did not manually disable the traction
control system using the information
display controls or the switch. If the
stability control and traction control light
is still illuminating steadily, have the
system serviced by an authorized dealer
immediately. Operating your vehicle with
the traction control disabled could lead
to an increased risk of loss of vehicle
control, vehicle rollover, personal injury
and death.
The system automatically turns on each
time you switch the ignition on.
If your vehicle is stuck in mud or snow,
switching traction control off may be
beneficial as this allows the wheels to spin.
Note: When you switch traction control off,
stability control remains fully active.
Note: For additional information on the
traction and stability control systems. See
Using Stability Control
(page 229). Switching the System Off
When you switch the system off or on, a
message appears in the information
display showing system status.
Use the traction and stability control
switch on the instrument panel to switch
the system off or on.
The switch illuminates when traction
control is off.
When you place your vehicle into
four-wheel drive low mode the traction
control disables. Traction control resumes
full operation when you put your vehicle
back into two-wheel drive mode.
System Indicator Lights and
Messages
The stability and traction control
light:
• Temporarily illuminates on engine
start-up.
• Flashes when a driving condition
activates either of the systems.
• Illuminates if a problem occurs in either
of the systems. The stability and traction control
off light temporarily illuminates
on engine start-up and stays on
when you switch the traction control
system off.
227
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Traction ControlE225465 E225466

PRINCIPLE OF OPERATION
WARNING: Hill descent control
cannot control descent in all surface
conditions and circumstances, such as
ice or extremely steep grades. Hill
descent control is a driver assist system
and cannot substitute for good judgment
by the driver. Failure to do so may result
in loss of vehicle control, crash or serious
injury. WARNING:
The system does not
replace the parking brake. When you
leave your vehicle, always apply the
parking brake and shift the transmission
into park (P) for automatic transmission
or first gear for manual transmission.
Hill descent control allows the driver to set
and maintain vehicle speed while
descending steep grades in various surface
conditions.
Hill descent control can maintain vehicle
speeds on downhill grades between 2 mph
(3 km/h)
and 12 mph (20 km/h). Above
20 mph (32 km/h), the system remains
armed, but descent speed cannot be set
or maintained.
Hill descent control requires a cooling
down interval after a period of sustained
use. The amount of time that the feature
can remain active before cooling varies
with conditions. The system will provide
a warning in the message center and a
chime will sound when the system is about
to disengage for cooling. At this time,
manually apply the brakes as needed to
maintain descent speed. USING HILL DESCENT
CONTROL Press and release the hill
descent button on the
instrument panel. A light in the
cluster illuminates and a tone sounds
when this feature is activated.
To increase descent speed, press the
accelerator pedal until the desired speed
is reached. To decrease descent speed,
press the brake pedal until the desired
speed is reached.
Whether accelerating or decelerating, once
the desired descent speed is reached,
remove your feet from the pedals and the
chosen vehicle speed is maintained.
Note: Noise from the ABS pump motor may
be observed during hill descent control
operation. This is a normal characteristic of
the ABS and should be no reason for
concern.
Hill Descent Modes
• At speeds below
20 mph (32 km/h):
When the hill descent control switch is
pressed and hill descent control is
active, the hill descent control telltale
flashes.
• At speeds below
20 mph (32 km/h):
When the hill descent control switch is
pressed and conditions are not correct
for hill descent activation, the hill
descent control system is enabled and
the hill descent control telltale is solid.
A message displays in the information
display.
• At speeds above
20 mph (32 km/h):
When the hill descent control switch is
pressed, the hill descent control
system is enabled, the telltale in the
cluster is not illuminated and a
message is displayed in the information
display.
232
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Terrain Control
(If Equipped)E163957