Porsche Cayenne 2020, Owner'S Manual

Page: 79 / 366

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Brakes
77
Footbrake
WARNING
Obstructed pedals
Unsuitable floor mats or floor mats that are not
properly secured can restrict the movement of the
pedals or interfere with actuation of the pedals. The
accelerator pedal can be depressed unintentionally
or the brake pedal blocked. This can result in an un-
expected increase in the driving speed or make
braking difficult.
e
Only use floor mats that are suitable for the
vehicle.
e
Secure the floor mats properly and do not lay
them loosely.
e
Do not lay several floor mats on top of each
other.
e Ensure that the floor mats are securely fitted
again after they have been removed, e.g. for
cleaning.
WARNING
No brake force boosting
The brake booster is only operative when the engine
is running. Consequently, much greater force needs
to be applied to the pedal during braking when the
engine is switched off or in the event of a faulty
brake booster.
e Vehicles with defective brakes must not be
towed.
>
Please see chapter "Towing" on page 270.
WARNING
Water film on brake disk
In heavy rain, when driving through water or after
washing the vehicle, the braking effect may be de-
layed and increased pressure on the brake pedal may
be required.
e
Allow a greater braking distance from the vehicle
in front and "brake" the brakes dry at intervals.
Always ensure that this does not affect the traf-
fic behind.
WARNING
Reduced braking action
After a long drive over salted or gritted roads, a
coating may form on the brake disks and pads that
significantly reduces friction and therefore the brak-
ing action as well.
The brake disks will inevitably begin to corrode if
your vehicle is parked for an extended period, lead-
ing to a tendency for the brakes to "rub".
e To prevent corrosion on the brake disks, the
brakes should be "braked dry" before parking the
vehicle (this does not apply to vehicles with Por-
sche Ceramic Composite Brakes).
e
If braking comfort is noticeably impaired, it is
recommended that you have the brake system
checked by experts.
Go to a qualified specialized repair shop. Porsche
recommends an authorized Porsche dealer, as
they have trained technicians and the necessary
parts and tools.
e
To relieve the brake system on steep slopes, re-
member to shift to a lower gear in good time
(engine braking effect).
If the engine braking effect on slopes is not suf-
ficient, use the footbrake at intervals. Continuous
braking can cause the brakes to overheat, im-
pairing their effectiveness.
For Information on brake fluid and checking the
brake fluid level:
>
Please see chapter "Brake Fluid" on page 75.
Brake system function
Porsche cars are equipped with a power assisted
hydraulic dual circuit brake system with disk brakes
at the front and rear.
Both circuits function independently. One brake cir-
cuit operates the front left and rear right wheel and
the other operates the front right and rear left wheel.
If one brake circuit fails, the other will still operate.
However, you will notice an increased pedal travel
when you apply the brakes. Failure of one brake cir-
cuit will cause the stopping distance to increase.
Responding to warning symbols
The functionality of the brake system warning light
can be checked by switching the ignition to the "On"
position (position 1 ) and verifying that the warning
light illuminates.
The warning light in the instrument panel lights up. A
message will be displayed in the instrument panel if
the brake fluid level is too low, or (if the brake pedal
travel has increased) one of the two brake circuits
has failed. A greater braking pressure will be re-
quired, stopping distances will be longer and the
braking behavior will change, particularly in curves.
For information on warning lights and light
indicators:
> Please see chapter "Instrument Cluster" on
page 139.
> Please see chapter "Warning and Information
Messages" on page 293.
Brake pads and brake disks
The wear on the brake pads and brake disks largely
depends on the driving style and the conditions of
use and cannot therefore be expressed in terms of
mileage covered.
The high performance brake system is designed to
ensure the best possible braking effect at all speeds
and temperatures.