light FORD F-450 2020 Repair Manual

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 215).
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.
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(If Equipped)LOC K
OTUAE339076

After driving through mud, clean off residue
stuck to rotating driveshafts and tires.
Excess mud stuck on tires and rotating
driveshafts can cause an imbalance that
could damage drive components.
Water
If you must drive through high water, drive
slowly. Traction or brake capability may
be limited.
When driving through water, determine the
depth and avoid water higher than the
bottom of the hubs. If the ignition system
gets wet, your vehicle may stall.
Once through water, always try the brakes.
Wet brakes do not stop your vehicle as
effectively as dry brakes. Drying can be
improved by applying light pressure to the
brake pedal while moving slowly.
Note:
Driving through deep water may
damage the transmission. If the front or rear
axle is submerged in water, the axle
lubricant and power transfer unit lubricant
should be checked and changed if
necessary.
Driving on Hilly or Sloping Terrain
Although natural obstacles may make it
necessary to travel diagonally up or down
a hill or steep incline, you should always
try to drive straight up or straight down.
Note: Avoid turning on steep slopes or
hills. A danger lies in losing traction, slipping
sideways and possible vehicle roll over.
Whenever driving on a hill, determine
beforehand the route you will use. Do not
drive over the crest of a hill without seeing
what conditions are on the other side. Do
not drive in reverse over a hill without the
aid of an observer.
When climbing a steep slope or hill, start
in a lower gear rather than downshifting to
a lower gear from a higher gear once the
ascent has started. This reduces strain on
the engine and the possibility of stalling. If your vehicle stalls, do not try to turn
around because this could cause vehicle
roll over. It is better to reverse back to a
safe location.
Apply just enough power to the wheels to
climb the hill. Too much power will cause
the tires to slip, spin or lose traction,
resulting in loss of vehicle control.
Descend a hill in the same gear you would
use to climb up the hill to avoid excessive
brake application and brake overheating.
Do not descend in neutral. Disengage
overdrive or move the transmission
selector lever to a lower gear. When
descending a steep hill, avoid sudden hard
braking as you could lose control. The front
wheels have to be turning in order to steer
your vehicle.
If your vehicle has anti-lock brakes, apply
the brakes steadily. Do not pump the
brakes.
Driving on Snow and Ice
WARNING: If you are driving in
slippery conditions that require tire
chains or cables, then it is critical that
you drive cautiously. Keep speeds down,
allow for longer stopping distances and
avoid aggressive steering to reduce the
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chances of a loss of vehicle control
which can lead to serious injury or death.
If the rear end of your vehicle slides while
cornering, steer in the direction of the
slide until you regain control of your
vehicle.
Note: Excessive tire slippage can cause
transmission damage.
Four-wheel drive vehicles have advantages
over two-wheel drive vehicles in snow and
ice but can skid like any other vehicle.
Should you start to slide while driving on
snowy or icy roads, turn the steering wheel
in the direction of the slide until you regain
control.
Avoid sudden applications of power and
quick changes of direction on snow and
ice. Apply the accelerator slowly and
steadily when starting from a full stop.
Avoid sudden braking. Although a
four-wheel drive vehicle may accelerate
better than a two-wheel drive vehicle in
snow and ice, it will not stop any faster as
braking occurs at all four wheels. Do not
become overconfident as to road
conditions.
Make sure you allow sufficient distance
between you and other vehicles for
stopping. Drive slower than usual and
consider using one of the lower gears. In
emergency stopping situations, apply the
brake steadily. Do not pump the brake
pedal. See Hints on Driving With
Anti-Lock Brakes (page 219).
If Your Vehicle Gets Stuck in Mud or
Snow WARNING:
Do not spin the wheels
at over 34 mph (55 km/h). The tires may
fail and injure a passenger or bystander. If your vehicle gets stuck in mud or snow,
it may be rocked out by shifting between
forward and reverse gears, stopping
between shifts in a steady pattern. Press
lightly on the accelerator in each gear.
Note:
Do not rock your vehicle if the engine
is not at normal operating temperature,
damage to the transmission may occur.
Note: Do not rock your vehicle for more
than a minute, damage to the transmission
and tires may occur or the engine may
overheat.
Parking WARNING:
If the parking brake is
fully released, but the brake warning
lamp remains illuminated, the brakes
may not be working properly. Have your
vehicle checked as soon as possible. WARNING:
Apply the parking
brake, shift into park (P), switch the
ignition off and remove the key before
you leave your vehicle. Failure to follow
this instruction could result in personal
injury or death.
On some four-wheel drive vehicles, when
the transfer case is in the neutral (N)
position, the engine and transmission are
disconnected from the rest of the driveline.
Therefore, the vehicle is free to roll even if
the automatic transmission is in park (P)
or the manual transmission is in gear. Do
not leave the vehicle unattended with the
transfer case in the neutral (N) position.
Always set the parking brake fully and turn
off the ignition when leaving the vehicle.
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(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.
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For 4WD vehicles
Pull the 4WD control knob toward you.
For 2WD vehicles
Turn the control to ON.
Once the indicator light
illuminates in the information
display, both rear wheel axle
shafts will be locked together providing
added traction.
If the indicator does not come on, or the
indicator turns off while driving, one of the
following has occurred:
• The vehicle speed is too high.
• The left and right rear wheel speed
difference is too high during an
engagement attempt. •
The system has malfunctioned and is
accompanied by a message in the
information display. See your
authorized Ford dealer for assistance.
• The vehicle is experiencing an anti-lock
brake activation.
Operating ELD With a Spare or
Mismatched Tires
On vehicles with an ELD, the size of the
spare tire can affect performance of the
system. If there is a significant difference
between the two rear tires, you may have
limited ELD functionality. If the electronic
locking differential has difficulty
disengaging, release the accelerator pedal
and turn the steering wheel in the opposite
direction when rolling. We recommend
engaging and disengaging the ELD at a
stop when you mount a spare on the rear
axle.
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GENERAL INFORMATION
Note:
Occasional brake noise is normal. If
a metal-to-metal, continuous grinding or
continuous squeal sound is present, the
brake linings may be worn-out. Have the
system checked by an authorized dealer. If
your vehicle has continuous vibration or
shudder in the steering wheel while braking,
have it checked by an authorized dealer.
Note: Brake dust may accumulate on the
wheels, even under normal driving
conditions. Some dust is inevitable as the
brakes wear and does not contribute to
brake noise.
Wet brakes result in reduced braking
efficiency. Gently press the brake pedal a
few times when driving from a car wash or
standing water to dry the brakes.
Brake Over Accelerator
In the event the accelerator pedal
becomes stuck or entrapped, apply steady
and firm pressure to the brake pedal to
slow the vehicle and reduce engine power.
If you experience this condition, apply the
brakes and bring your vehicle to a safe
stop. Shift the transmission to park (P),
switch the engine off and apply the parking
brake. Inspect the accelerator pedal for
any interference. If none are found and the
condition persists, have your vehicle towed
to the nearest authorized dealer.
Brake Assist
Brake assist detects when you brake
rapidly by measuring the rate at which you
press the brake pedal. It provides
maximum braking efficiency as long as you
press the pedal, and can reduce stopping
distances in critical situations. Anti-lock Brake System
This system helps you maintain steering
control during emergency stops by keeping
the brakes from locking. This lamp momentarily
illuminates when you switch the
ignition on. If the light does not
illuminate during start up, remains on or
flashes, the system may be disabled. Have
the system checked by an authorized
dealer. If the anti-lock brake system is
disabled, normal braking is still effective.
See Warning Lamps and Indicators
(page 104).
Note: Indicators vary depending on region. If the lamp remains illuminated
after you release the parking
brake, have the system checked
by an authorized dealer.
It also illuminates momentarily
when you switch the ignition on
to confirm the lamp is functional. If it does
not illuminate when you switch the ignition
on, or begins to flash at any time, have the
system checked by an authorized dealer.
Diesel Engine Exhaust Braking
(If
Equipped) WARNING:
Do not use tow/haul
when the road surface is slippery. Failure
to follow this instruction could result in
the loss of control of your vehicle. WARNING:
Do not use diesel
engine exhaust braking when the road
surface is slippery. Failure to follow this
instruction could result in the loss of
control of your vehicle.
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When the system is active, your vehicle
remains stationary on the slope for two to
three seconds after you release the brake
pedal. This allows time to move your foot
from the brake to the accelerator pedal.
The system releases the brakes
automatically once the engine has
developed sufficient torque to prevent your
vehicle from rolling down the slope. This
is an advantage when pulling away on a
slope, for example from a car park ramp,
traffic lights or when reversing uphill into
a parking space.
The system activates on any slope that
causes your vehicle to roll.
Note:
There is no warning light to indicate
the system is either on or off.
Using Hill Start Assist
1. Press the brake pedal to bring your vehicle to a complete standstill. Keep
the brake pedal pressed and shift into
first gear when facing uphill or reverse
(R) when facing downhill.
2. If the sensors detect that your vehicle is on a slope, the system activates
automatically.
3. When you remove your foot from the brake pedal, your vehicle remains on
the slope without rolling away for
about two to three seconds. This hold
time automatically extends if you are
in the process of driving off.
4. Drive off in the normal manner. The system releases the brakes
automatically.
Note: When you remove your foot from the
brake pedal and press the pedal again when
the system is active, you will experience
significantly reduced brake pedal travel. This
is normal. Switching the System On and Off
Vehicles with Manual Transmission
You can switch this feature on or off in the
information display. The system
remembers the last setting when you start
your vehicle.
Vehicles with Automatic Transmission
You cannot turn the system on or off.
When you switch the ignition on, the
system automatically turns on.
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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 223). 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.
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PRINCIPLE OF OPERATION
WARNING: Vehicle modifications
involving braking system, aftermarket
roof racks, suspension, steering system,
tire construction and wheel and tire size
may change the handling characteristics
of your vehicle and may adversely affect
the performance of the electronic
stability control system. In addition,
installing any stereo loudspeakers may
interfere with and adversely affect the
electronic stability control system. Install
any aftermarket stereo loudspeaker as
far as possible from the front center
console, the tunnel, and the front seats
in order to minimize the risk of interfering
with the electronic stability control
sensors. Reducing the effectiveness of
the electronic stability control system
could lead to an increased risk of loss of
vehicle control, vehicle rollover, personal
injury and death. WARNING:
Remember that even
advanced technology cannot defy the
laws of physics. It’ s always possible to
lose control of a vehicle due to
inappropriate driver input for the
conditions. Aggressive driving on any
road condition can cause you to lose
control of your vehicle increasing the risk
of personal injury or property damage.
Activation of the electronic stability
control system is an indication that at
least some of the tires have exceeded
their ability to grip the road; this could
reduce the operator ’s ability to control
the vehicle potentially resulting in a loss
of vehicle control, vehicle rollover,
personal injury and death. If your
electronic stability control system
activates, SLOW DOWN.
The system automatically turns on each
time you switch the ignition on. If a fault occurs in either the stability
control or the traction control system, you
may experience the following conditions:
•
The stability and traction control light
illuminates steadily.
• The stability control and traction
control systems do not enhance your
vehicle's ability to maintain traction of
the wheels.
• The Adaptive Steering system (if
equipped) automatically changes the
steering function to a fixed steering
ratio. See
Steering (page 256).
If a driving condition activates either the
stability control or the traction control
system you may experience the following
conditions:
• The stability and traction control light
flashes.
• Your vehicle slows down.
• Reduced engine power.
• A vibration in the brake pedal.
• The brake pedal is stiffer than usual.
• If the driving condition is severe and
your foot is not on the brake, the brake
pedal may move as the system applies
higher brake force.
The stability control system has several
features built into it to help you maintain
control of your vehicle:
Electronic Stability Control
The system enhances your vehicle ’s ability
to prevent skids or lateral slides by
applying brakes to one or more of the
wheels individually and, if necessary,
reducing engine power.
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AdvanceTrac with RSC Features
Traction
control system
Electronic
stabilitycontrol
Roll stability
control
Stability
control light
Button func-
tions
Enabled
Enabled
Enabled
Illuminated
during bulb check
Default at start-
up
Disabled
Enabled 1
Enabled
Illuminated
Button pressed
momentarily
Disabled
Disabled
Disabled
illuminated 3
Button pressed
and held for
more than 5 seconds
Enabled2
Enabled 1
Enabled
Illuminated
Double Press
(Pickup Only)
Enabled
Enabled
Enabled
Not illuminated
Button pressed
again after
deactivation
Disabled
Disabled
Disabled
Illuminated
Transfer case
switched to
4WD Low 4
1 Electronic stability control has reduced sensitivity compared to a fully active system.
2 Traction control has reduced sensitivity compared to a fully active system.
3 Lamp light starts blinking for four seconds after entering the press and hold state.
4 Engaging 4WD Low disables roll stability control, electronic stability control and the
traction control systems.
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