2021 INFINITI QX80 brakes

5-120Starting and driving
WARNING
.Never rely solely on the hill start
assist system to prevent the vehicle
from moving backward on a hill.
Always drive carefully and atten-
tively. Depress the brake pedal when
the vehicle is stopped on a steep hill.
Be especially careful when stopped
on a hill on frozen or muddy roads.
Failure to prevent the vehicle from
rolling backwards may result in a loss
of control of the vehicle and possible
serious injury or death.
. The hill start assist system is not
designed to hold the vehicle at a
standstill on a hill. Depress the brake
pedal when the vehicle is stopped on
a steep hill. Failure to do so may
cause the vehicle to roll backwards
and may result in a collision or serious
personal injury.
. The hill start assist system may not
prevent the vehicle from rolling back-
wards on a hill under all load or road
conditions. Always be prepared to
depress the brake pedal to prevent
the vehicle from rolling backwards.
Failure to do so may result in a
collision or serious personal injury. The hill start assist system automatically
keeps the brakes applied to help prevent the
vehicle from rolling backwards in the time it
takes the driver to release the brake pedal
and apply the accelerator when the vehicle is
stopped on a hill.
The hill start assist system will operate
automatically under the following condi-
tions:
.
The transmission is shifted to a forward
or reverse gear.
. The vehicle is stopped completely on a hill
by applying the brake.
The maximum holding time is 2 seconds.
After 2 seconds the vehicle will begin to roll
back and the hill start assist system will stop
operating completely.
The hill start assist system will not operate
when the transmission is shifted to the N
(Neutral) or P (Park) position or on a flat and
level road.
When the Vehicle Dynamic Control (VDC)
warning light illuminates in the meter, the hill
start assist system will not operate. (See
“Warning lights, indicator lights and audible
reminders” (P.2-11).)
HILL START ASSIST SYSTEM

WARNING
If the engine is not running or is turned
off while driving, the power assist for
the steering will not work. Steering will
be harder to operate.
The power assisted steering uses a hydraulic
pump, driven by the engine, to assist steer-
ing.
If the engine stops or the drive belt breaks,
you will still have control of the vehicle.
However, much greater steering effort is
needed, especially in sharp turns and at low
speeds.
BRAKING PRECAUTIONS
The brake system has two separate hydrau-
lic circuits. If one circuit malfunctions, you
will still have braking ability at two wheels.
You may feel a small click and hear a sound
when the brake pedal is fully depressed
slowly. This is not a malfunction and in-
dicates that the brake assist mechanism is
operating properly.
Hydraulically-assisted brakes
The hydraulically-assisted brake system is
designed to use a hydraulic pump driven
electrically, to assist braking. If the engine
stops, you can stop the vehicle by depressing
the foot brake pedal. However, greater foot
pressure on the foot brake pedal will be
required to stop the vehicle. The stopping
distance will be longer.
Wet brakes
When the vehicle is washed or driven
through water, the brakes may get wet. As
a result, your braking distance will be longer
and the vehicle may pull to one side during
braking.
To dry brakes, drive the vehicle at a safe
speed while lightly tapping the brake pedal
to heat-up the brakes. Do this until the
brakes return to normal. Avoid driving the
vehicle at high speeds until the brakes function correctly.
PARKING BRAKE BREAK-IN
Break in the parking brake shoes whenever
the stopping effect of the parking brake is
weakened or whenever the parking brake
shoes and/or drums/rotors are replaced, in
order to assure the best braking perfor-
mance.
This procedure is described in the vehicle
service manual. It is recommended you visit
an INFINITI retailer for this service.
Using the brakes
Avoid resting your foot on the brake pedal
while driving. This will cause overheating of
the brakes, wearing out the brake and pads
faster and reduce gas mileage.
To help save the brakes and to prevent the
brakes from overheating, reduce speed and
downshift to a lower gear before going
down a slope or long grade. Overheated
brakes may reduce braking performance and
could result in loss of vehicle control.
WARNING
.
While driving on a slippery surface,
be careful when braking, accelerating
or downshifting. Abrupt braking or
accelerating could cause the wheels
Starting and driving5-123
POWER STEERING BRAKE SYSTEM

5-124Starting and driving
to skid and result in an accident.
. If the engine is not running or is
turned off while driving, the power
assist for the brakes will not work.
Braking will be harder.BRAKE ASSIST
When the force applied to the brake pedal
exceeds a certain level, the Brake Assist is
activated generating greater braking force
than a conventional brake booster even with
light pedal force.
WARNING
The Brake Assist is only an aid to assist
braking operation and is not a collision
warning or avoidance device. It is the
driver’s responsibility to stay alert, drive
safely and be in control of the vehicle at
all times.
ANTI-LOCK BRAKING SYSTEM
(ABS)
WARNING
.The Anti-lock Braking System (ABS)
is a sophisticated device, but it
cannot prevent accidents resulting
from careless or dangerous driving
techniques. It can help maintain ve-
hicle control during braking on slip-
pery surfaces. Remember that
stopping distances on slippery sur- faces will be longer than on normal
surfaces even with ABS. Stopping
distances may also be longer on
rough, gravel or snow covered roads,
or if you are using tire chains. Always
maintain a safe distance from the
vehicle in front of you. Ultimately,
the driver is responsible for safety.
. Tire type and condition may also
affect braking effectiveness.
— When replacing tires, install the specified size of tires on all four
wheels.
— When installing a spare tire, make sure that it is the proper size and
type as specified on the Tire and
Loading Information label. See
“Tire and loading information la-
bel” (P.10-13).
— For detailed information, see “Wheels and tires” (P.8-27).
The Anti-lock Braking System (ABS) controls
the brakes so the wheels do not lock during
hard braking or when braking on slippery
surfaces. The system detects the rotation
speed at each wheel and varies the brake
fluid pressure to prevent each wheel from
locking and sliding. By preventing each
wheel from locking, the system helps the
BRAKE ASSIST

driver maintain steering control and helps to
minimize swerving and spinning on slippery
surfaces.
Using the system
Depress the brake pedal and hold it down.
Depress the brake pedal with firm steady
pressure, but do not pump the brakes. The
ABS will operate to prevent the wheels from
locking up. Steer the vehicle to avoid
obstacles.
WARNING
Do not pump the brake pedal. Doing so
may result in increased stopping dis-
tances.
Self-test feature
The ABS includes electronic sensors, electric
pumps, hydraulic solenoids and a computer.
The computer has a built-in diagnostic
feature that tests the system each time you
start the engine and move the vehicle at a
low speed in forward or reverse. When the
self-test occurs, you may hear a “clunk”
noise and/or feel a pulsation in the brake
pedal. This is normal and does not indicate a
malfunction. If the computer senses a mal-
function, it switches the ABS off andilluminates the ABS warning light on the
instrument panel. The brake system then
operates normally, but without anti-lock
assistance.
If the ABS warning light illuminates during
the self-test or while driving, have the
vehicle checked. It is recommended you visit
an INFINITI retailer for this service.
Normal operation
The ABS operates at speeds above 3 to 6
MPH (5 to 10 km/h). The speed varies
according to road conditions.
When the ABS senses that one or more
wheels are close to locking up, the actuator
rapidly applies and releases hydraulic pres-
sure. This action is similar to pumping the
brakes very quickly. You may feel a pulsation
in the brake pedal and hear a noise from
under the hood or feel a vibration from the
actuator when it is operating. This is normal
and indicates that the ABS is operating
properly. However, the pulsation may indi-
cate that road conditions are hazardous and
extra care is required while driving.
The Vehicle Dynamic Control (VDC) system
uses various sensors to monitor driver inputs
and vehicle motion. Under certain driving
conditions, the VDC system helps to perform
the following functions.
.
Controls brake pressure to reduce wheel
slip on one slipping drive wheel so power
is transferred to a non slipping drive
wheel on the same axle.
. Controls brake pressure and engine out-
put to reduce drive wheel slip based on
vehicle speed (traction control function).
. Controls brake pressure at individual
wheels and engine output to help the
driver maintain control of the vehicle in
the following conditions:
— understeer (vehicle tends to not follow the steered path despite increased
steering input)
— oversteer (vehicle tends to spin due to certain road or driving conditions).
The VDC system can help the driver to
maintain control of the vehicle, but it cannot
prevent loss of vehicle control in all driving
situations.
When the VDC system operates, the VDC
warning light
in the instrument panel
flashes so note the following:
. The road may be slippery or the system
may determine some action is required to
help keep the vehicle on the steered path.
Starting and driving5-125
VEHICLE DYNAMIC CONTROL
(VDC) SYSTEM

8 Do-it-yourself
Maintenance precautions ............................................... 8-2
Engine compartment check locations ......................... 8-3VK56VD engine model .............................................. 8-3
Engine cooling system ..................................................... 8-4 Checking engine coolant level ................................. 8-5
Changing engine coolant .......................................... 8-5
Engine oil ........................................................................\
..... 8-6 Checking engine oil level ........................................... 8-6
Changing engine oil and filter .................................. 8-6
Automatic Transmission Fluid (ATF) .......................... 8-8
Power steering fluid ......................................................... 8-8
Brake fluid ........................................................................\
... 8-9 Brake fluid ..................................................................... 8-9
Window washer fluid ................................................... 8-10
Battery ........................................................................\
....... 8-11 Jump starting ............................................................. 8-12
Variable voltage control system ................................. 8-13
Drive belts ........................................................................\
. 8-13
Spark plugs ....................................................................... 8-14 Replacing spark plugs .............................................. 8-14
Air cleaner ........................................................................\
. 8-14 Windshield wiper blades .............................................. 8-15
Cleaning ..................................................................... 8-15
Replacing ................................................................... 8-16
Rear window wiper blades .......................................... 8-16
Brakes ........................................................................\
........ 8-17 Self-adjusting brakes ............................................. 8-17
Brake pad wear warning ....................................... 8-17
Brake booster ........................................................... 8-17
Fuses ........................................................................\
.......... 8-18 Engine compartment .............................................. 8-18
Passenger compartment ...................................... 8-20
Intelligent Key battery replacement ......................... 8-21
Lights ........................................................................\
......... 8-23
Headlights ................................................................ 8-24
Exterior and interior lights ................................... 8-24
Wheels and tires ............................................................. 8-27
Tire pressure ............................................................. 8-27
Tire labeling .............................................................. 8-31
Types of tires ........................................................... 8-33
Tire chains ................................................................ 8-34
Changing wheels and tires ................................... 8-35

If the brakes do not operate properly, have
the brakes checked. It is recommended that
you visit an INFINITI retailer for this service.
SELF-ADJUSTING BRAKES
Your vehicle is equipped with self-adjusting
brakes.
The disc-type brakes self-adjust every time
the brake pedal is applied.
WARNING
Have your brake system checked if the
brake pedal height does not return to
normal. It is recommended you visit an
INFINITI retailer for this service.
BRAKE PAD WEAR WARNING
The disc brake pads have audible wear
warnings. When a brake pad requires repla-
cement, it will make a high pitched scraping
sound when the vehicle is in motion. This
scraping sound will first occur only when the
brake pedal is depressed. After more wear of
the brake pad, the sound will always be
heard even if the brake pedal is not
depressed. Have the brakes checked as soon
as possible if the wear warning sound is
heard.
Under some driving or climate conditions,occasional brake squeak, squeal or other
noise may be heard. Occasional brake noise
during light to moderate stops is normal and
does not affect the function or performance
of the brake system.
Proper brake inspection intervals should be
followed.
For additional information, see the
maintenance schedules shown in the “9.
Maintenance and schedules” section.
BRAKE BOOSTER
Check the brake booster function as follows:
1. With the engine off, depress and release the foot brake pedal more than 20 times.
When the foot brake pedal movement
(distance of travel) remains the same
from one pedal application to the next,
continue on to the next step.
2. While depressing the foot brake pedal, start the engine.
3. With the foot brake pedal depressed, stop the engine. Keep the pedal de-
pressed for about 30 seconds.
4. Run the engine for 1 minute without depressing the foot brake pedal, then
turn it off. Depress the foot brake pedal
several times. The pedal travel distance
will decrease gradually with each de-
pression as the hydraulic pressure de-
creases. If the brakes do not operate properly, have
the brakes checked. It is recommended that
you visit an INFINITI retailer for repair.
Do-it-yourself8-17
BRAKES

When driving in areas using road salt or
other corrosive materials, check lubrication
frequently.
Lights*:Clean the headlights on a regular
basis. Make sure that the headlights, stop
lights, tail lights, turn signal lights, and other
lights are all operating properly and installed
securely. Also check headlight aim.
Road wheel nuts (lug nuts)*: When checking
the tires, make sure no wheel nuts are
missing, and check for any loose wheel nuts.
Tighten if necessary.
Tire rotation*: Rotate tires at the specified
interval shown in the maintenance schedule.
Tires*: Check the pressure with a gauge
often and always prior to long distance trips.
If necessary, adjust the pressure in all tires,
including the spare, to the pressure speci-
fied. Check carefully for damage, cuts or
excessive wear.
Tire Pressure Monitoring System (TPMS)
transmitter components: Replace the TPMS
transmitter grommet seal, valve core and
cap when the tires are replaced due to wear
or age.
Wheel alignment and balance: If the vehicle
should pull to either side while driving on a
straight and level road, or if you detect
uneven or abnormal tire wear, there may be
a need for wheel alignment. If the steering wheel or seat vibrates at
normal highway speeds, wheel balancing
may be needed.
For additional information regarding tires,
refer to “Important Tire Safety Information”
(US) or “Tire Safety Information” (Canada) in
the INFINITI Warranty Information Booklet.
Windshield:
Clean the windshield on a
regular basis. Check the windshield at least
every six months for cracks or other damage.
Have a damaged windshield repaired by a
qualified repair facility. It is recommended
that you have a damaged windshield re-
paired by an INFINITI retailer, or an INFINITI
Certified Collision Center. To locate a colli-
sion center in your area, refer to http://
collision.infinitiusa.com.
Windshield wiper blades*: Check for cracks
or wear if they do not wipe properly.
Inside the vehicle
The maintenance items listed here should be
checked on a regular basis, such as when
performing periodic maintenance, cleaning
the vehicle, etc.
Accelerator pedal: Check the pedal for
smooth operation and make sure the pedal
does not catch or require uneven effort.
Keep the floor mat away from the pedal.
Automatic transmission P (Park) mechan-
ism: On a fairly steep hill, check that your vehicle is held securely with the shift lever in
the P (Park) position without applying any
brakes.
Brake pedal:
Check the pedal for smooth
operation. If the brake pedal suddenly goes
down further than normal, the pedal feels
spongy or the vehicle seems to take longer to
stop, have your vehicle checked immediately.
It is recommended you visit an INFINITI
retailer for this service. Keep the floor mat
away from the pedal.
Brakes: Check that the brakes do not pull the
vehicle to one side when applied.
Parking brake: Check the parking brake
operation regularly. The vehicle should be
securely held on a fairly steep hill with only
the parking brake applied. If the parking
brake needs adjusted, it is recommended you
visit an INFINITI retailer for this service.
Seat belts: Check that all parts of the seat
belt system (for example, buckles, anchors,
adjuster and retractors) operate properly
and smoothly, and are installed securely.
Check the belt webbing for cuts, fraying,
wear or damage.
Seats: Check seat position controls such as
seat adjusters, seatback recliner, etc. to
ensure they operate smoothly and that all
latches lock securely in every position. Check
that the head restraints/headrests move up
and down smoothly and that the locks (if so
Maintenance and schedules9-3

cause serious personal injury or property
damage.
Hitch ball
Choose a hitch ball of the proper size and
weight rating for your trailer:
.The required hitch ball size is stamped on
most trailer couplers. Most hitch balls
also have the size printed on top of the
ball.
. Choose the proper class hitch ball based
on the trailer weight.
. The diameter of the threaded shank of
the hitch ball must be matched to the ball
mount hole diameter. The hitch ball
shank should be no more than 1/16”
smaller than the hole in the ball mount.
. The threaded shank of the hitch ball must
be long enough to be properly secured to
the ball mount. There should be at least 2
threads showing beyond the lock washer
and nut.
Ball mount
The hitch ball is attached to the ball mount
and the ball mount is inserted into the hitch
receiver. Choose a proper class ball mount
based on the trailer weight. Additionally, the
ball mount should be chosen to keep the
trailer tongue level with the ground.
Weight carrying hitches
A weight carrying or “dead weight” ball
mount is one that is designed to carry the
whole amount of tongue weight and gross
weight directly on the ball mount and on the
receiver.
Weight distribution hitch
This type of hitch is also called a “load-
leveling” or “equalizing” hitch. A set of bars
attach to the ball mount and to the trailer to
distribute the tongue weight (hitch weight)
of your trailer. Many vehicles cannot carry
the full tongue weight of a given trailer, and
need some of the tongue weight transferred
through the frame and pushing down on the
front wheels. This gives stability to the tow
vehicle.
A weight-distributing hitch system (Class IV)
is recommended if you plan to tow trailers
with a maximum weight over 5,000 lbs
(2,267 kg). Check with the trailer and towing
equipment manufacturers to determine if
they recommend the use of a weight-
distributing hitch system.
NOTE:
A weight-distributing hitch system may
affect the operation of trailer surge brakes.
If you are considering use of a weight-
distributing hitch system with a surge brake-equipped trailer, check with the
surge brake, hitch or trailer manufacturer
to determine if and how this can be done.
Follow the instructions provided by the
manufacturer for installing and using the
weight-distributing hitch system.
General set-up instructions are as follows:
1. Park unloaded vehicle on a level surface.
With the ignition switch in the ON
position and the doors closed, allow the
vehicle to stand for several minutes so
that it can level.
2. Measure the height of a reference point on the front and rear bumpers at the
center of the vehicle.
3. Attach the trailer to the vehicle and adjust the hitch equalizers so that the
front bumper height is within 0 - .5
inches (0 - 13 mm) of the reference
height measured in step 2. The rear
bumper should be no higher than the
reference height measured in step 2.
WARNING
Properly adjust the weight distributing
hitch so the rear of the bumper is no
higher than the measured reference
height when the trailer is attached. If
the rear bumper is higher than the
Technical and consumer information10-25