70
Controls, Instruments
Operation of the ABS systemA wheel speed sensor is mounted to each of the
four wheels. If wheel lock-up of either of the front
wheels or the rear wheels is sensed during brak-
ing, the brake pressure is adjusted automatically
until the wheel no longer slips. The brake pressure
is regulated for each front wheel individually and
for both of the rear wheels together.
On a road surface which is slippery on only one
side, the rear wheel which is braking on the slip-
pery surface determines the brake pressure which
will be applied equally to both rear wheels. This en-
sures that directional stability is maintained. How-
ever, if braking forces approach the wheel lock-up
point for all wheels (panic braking) the ABS system
will intervene to provide a rapid rythmic braking.
The proper operation of ABS is perceived by the
driver as a pulsating brake pedal in conjunction
with audible noise and perhaps some vibration.
fIf you experience these sensations while driv-
ing or a road surface with questionable trac-
tion, reduce vehicle speed appropriate for the
prevailing road conditions.
The functional readiness of all the main electrical
components of the ABS is checked by an
electronic monitoring system both before and
while you drive. When the ignition is switched on the ABS warning
light will light up while the system is electronically
interrogated and goes out when the engine is
started if the check is not yet complete.
If the ABS warning lamp fails to go out, this indi-
cates that ABS has been deactivated due to a
fault. If the warning lights in the instrument panel
and on-board computer light up while you are driv-
ing, this indicates that a fault has occurred. In both
cases, normal braking, as in vehicles without ABS,
is still retained.
The ABS system should, however, be examined at
an authorized Porsche dealer immediately to pre-
vent the occurrence of further faults.
fIf the ABS system becomes inoperative, take
your vehicle to your authorized Porsche dealer
immediately.
Warning!
The control unit of the ABS brake system is
set for standard tire size. If non-standard
tires are installed, the control unit may mis-
interpret the speed of the vehicle, because of
the variant data it receives from the sensors
on the axles.
fUse only tire makes and types tested by Porsche.
Warning light USA
Warning light Canada
Controls, Instruments
109
TPC
Tire pressure monitoringPlease observe the chapter “TIRE PRESSURES” on
Page 232.
The tire pressure monitoring continuously
monitors tire pressure and tire temperature on all
four wheels and warns the driver when the tire
pressure is too low.
The display as well as the settings for the tire
pressure monitoring take place on the on-board
computer.
However, you must still adjust the tire pressure on
the wheel.
fThe driver is responsible for filling the tires
correctly and making the correct settings on
the on-board computer.
The tire pressure monitoring offers the following
functions:
– Display of the actual tire pressure while the
vehicle is in motion
– Display of the deviation from the required
pressure (refilling pressure)
– Display of currently set tire size and type
– Tire pressure warnings in two stages
Safety notes!
Despite the advantages offered by the tire
pressure monitoring, it is still the driver’s
responsibility to update the corresponding
settings in the on-board computer and
maintain the pressure in the tires. Low tire
pressure reduces the road safety of the
vehicle and destroys the tire and wheel.
fWhen a flat tire has been displayed, immedi-
ately stop in a suitable place and check the
tires for damage. If necessary, remedy the
damage with a tire sealant.
fDo not by any means continue to drive with
damaged tires.
fSealing the tire with tire sealant is only an
emergency repair, so you can drive to the next
authorized Porsche dealer. The maximum per-
mitted speed is 50 mph (80 km/h).
fDo not drive with tires whose tire pressure
drops again in a short period of time. In cases
of doubt, have tires checked by an authorized
Porsche dealer.
fDamaged tires must be immediately replaced
by an authorized Porsche dealer.
Tire repairs are not permissible under any
circumstances.fIf the tire pressure monitoring is defective (e.g.
defective wheel transmitter), contact an
authorized Porsche dealer immediately and
have the damage repaired.
The tire pressure will not be monitored by a
defective tire pressure monitoring.
fTires lose air over time without a tire defect
being present. A tire pressure warning will then
appear in the on-board computer display.
Correct the tire pressure at the next oppor-
tunity.
fThe tire pressure monitoring gives a warning
about tire damage due to natural pressure loss
as well as about a gradual loss of pressure due
to foreign objects.
The tire pressure monitoring cannot warn you
about tire damage that occurs suddenly (e.g.
flat tire due to abrupt external effects).
Controls, Instruments
111
Tire type info in Tire pressure menu
Information about the currently set tires:
–Tire type:
Summer tires, winter tires
–Tire size:
18, 19 inch
“Info tires” shows the current tire settings.
Calling up the “Info tires” display
fPush operating lever forward in order to switch
on the selection field.
fSelect “TPC” with the operating lever.
fPush operating lever forward.
The display changes to the Tire pressure
menu.
fSelect “Info tires” with the operating lever.
fPush operating lever forward.Tire selection in the “Set” menu
fPush operating lever forward in order to switch
on the selection field.
fSelect “TPC” with the operating lever.
fPush operating lever forward.
The display changes to the Tire pressure
menu.fSelect “Set” with the operating lever.
fPush the operating lever forward.
fSelect desired tire type:
summer or winter.
fPush operating lever forward.
A display for confirming the selected type of
tire appears.
f f f
112
Controls, Instruments fSelect “Continue” and push the operating lever
forward.
fSelect the appropriate tire size (18 or 19 inch)
and push operating lever forwards.
A display for confirming the selected tire size
appears.
Note
This menu is only displayed when different tire
sizes are approved.fSelect “Continue” and push the operating lever
forward.
Setting of the tire characteristics has only been
successfully completed when the message
“Process complete” is displayed by the on-board
computer.
fSelect arrow (Back) and push the operating
lever forward. The display returns to the Tire
pressure menu.
The on-board computer additionally displays
the message “System learning”.Note
The message “Process aborted” appears if the
setting process is interrupted. All entries made up
to this point are lost, and the original settings
remain in effect.
Only if the message “Process complete” appears
after the settings have been made will the tire
pressure monitoring re-learn the wheels.
fPlease observe the chapter “SYSTEM
LEARNING” on Page 115.
Before fitting tires with sizes which are not stored
in the on-board computer, the missing information
should be supplemented in the on-board
computer.
fConsult a qualified specialist garage. We
recommend that you use a Porsche partner for
this work since these are staffed with trained
personnel and have the necessary parts and
tools.
fUse only tires approved by Porsche.
The available items in the Tire pressure menu
depend on the equipment of your vehicle. For this
reason it is possible that some of the items shown
here are not available on your on-board
computer’s display.
232
Practical Tips, Emergency Service
Tire pressures
Warning!
Incorrect tire pressure causes increased tire
wear and adversely affects road handling.
fAlways use an accurate tire pressure gauge
when checking inflation pressures.
fDo not exceed the maximum tire pressure list-
ed on the tire sidewall.
Please observe the chapter “TIRE PRESSURE
PLATE” on Page 285.
fCold tire inflation pressure means: all tires
must be cold, ambient temperature maximum
(68°F/20°C)
, when adjusting the inflation pres-
sure.
Avoid sunlight striking the tires before measur-
ing cold pressures, since the pressures would
rise from temperature influence.
fValve caps protect the valve from dust and dirt,
and thus from leakage.
Always screw caps tightly down.
Replace missing caps immediately.
fUse only plastic valve caps.
fDo not use commercially available sealant or
tire inflating bottles. Only use Porsche approved tire sealant.Each tire, including the spare (if provided), should
be checked every 2 weeks when cold (68°F/20°C)
and inflated to the inflation pressure recommend-
ed in this Owner's Manual or on the tire-pressure
plate.
If your vehicle has tires of a different size than the
size indicated in this Owner's Manual or on the tire-
pressure plate, you should determine the proper
tire inflation pressure for those tires.
As an added safety feature, your vehicle has been
equipped with a tire pressure monitoring (TPC)
that illuminates a low tire pressure message when
one or more of your tires is significantly under-in-
flated. Accordingly, when the low tire pressure
message illuminates, you should stop and check
your tires as soon as possible, and inflate them to
the proper pressure. Driving on a significantly un-
der-inflated tire causes the tire to overheat and
can lead to tire failure. Under-inflation also reduc-
es fuel efficiency and tire tread life, and may affect
the vehicle’s handling and stopping ability.
Please note that the TPC is not a substitute for
proper tire maintenance, and it is the driver’s re-
sponsibility to maintain correct tire pressure, even
if under-inflation has not reached the level to trig-
ger illumination of the TPC low tire pressure mes-
sage.
fOn vehicles with tire pressure monitoring:
Please observe the chapter “TPC TIRE
PRESSURE MONITORING” on Page 109.
When tires are warm, the tire pressure is
increased.fNever let air out of hot tires.
This could cause the tire pressure to fall below
the prescribed value.
Insufficient tire filling pressure can cause tires to
overheat and thus be damaged – even invisibly.
Hidden tire damage is not eliminated by subse-
quently correcting the tire pressure.
Overloading
Danger!
Risk of personal injury, loss of control and
damage to vehicle parts.
fDo not overload your vehicle. Be careful about
the roof load.
fIf loading the vehicle also correct the tire pres-
sure. Tire pressure for loaded vehicle can be
found on the tire pressure plate and in the
chapter technical data.
fNever exceed the specified axle load.
Overloading can shorten the service life of the
tires and car, as well as lead to dangerous ve-
hicle reactions and long braking distances.
Damage due to overloading is not covered by the vehicle warranty.
fPlease observe the chapter “LOADING INFOR-
MATION” on Page 242.
fPlease observe the chapter “TIRE PRESSURES
FOR COLD TIRES” on Page 290.
Practical Tips, Emergency Service
233
Example of a tire pressure plate ATire pressure plateDepending on when your vehicle was manufac-
tured, the tire pressure plate on the driver's door
aperture will contain different data.
Information on the tire pressure plate A
A Seating capacity
Maximum number of vehicle occupants, includ-
ing the driver.B Vehicle load limit
Is the maximum total weight limit specified of
the load (passengers and cargo) for the vehi-
cle. This is the maximum weight of passengers
and cargo that can be loaded into the vehicle.
If a trailer is being towed, the trailer tongue
weight must be included as part of the cargo
load.
Please observe the chapter “LOADING INFOR-
MATION” on Page 242.
C Tire size for the front axle
Check with your authorized Porsche dealer
about the current release status.
D Recommended tire pressure for the front axle
These values are for cold tires (68°F/20°C).
E Tire size for the rear axle
Check with your authorized Porsche dealer
about the current release status.
F Recommended tire pressure for the rear axle
These values are for cold tires (68°F/20°C).
G In vehicles with collapsible spare wheel:
Size and tire pressure of the spare wheel
Example of a tire pressure plate BInformation on the tire pressure plate B
A Information for tire sealant, seating capacity,
vehicle load limit
B Approved tire size for the front axle
C Permissible tire pressure for the front axle
D Tire pressure for fully loaded or partially
loaded vehicle
E Permissible tire pressure for the rear axle
F Approved tire size for the rear axle
240
Practical Tips, Emergency Service
Example of InscriptionInscription on radial tireATire size
Example: P 295/30 ZR 19 100 Y
–P - The tire is designed for Passenger vehicle.
This information is not included on all tires.
–295 - Indication of tire width in mm
–30 - Indication of tire height to tire width ratio
in percent–ZR - code letter for radial tires for speeds
above 150 mph / 240 km/h
There are currently no standards concerning
tire strength at speeds above 150 mph
(240 km/h).
–R - Belt type code letter for radial
–19 - Indication of rim diameter in inches
–100 - Load capacity coefficient
–Y - Speed code letter
–XL (Extra Load) - Tire with increased load rat-
ing
B TIN (Tire Identification Number)
Example: DOT xx xx xxxx xxxx
–DOT
The DOT symbol indicates that the tires com-
ply with the requirements of the US Depart-
ment of Transportation and provides informa-
tion about:
– first two-digit code means manufacture’s iden-
tification mark.
– second two-digit code means tire size.
– third four-digit code means tire type code.
– fourth four-digit code means date of manufac-
ture.
If, for example, the last four numbers read
0204, the tire was produced in the 2nd week
of 2004.
C Tire ply composition and material
The number of layers in the tread and sidewalls
and their material composition.
D Maximum permissible inflation pressure
The maximum permissible cold inflation pressure
to which a tire can be inflated.
fDo not exceed the permissible inflation pres-
sure.
288
Technical Data
Tires, Rims, Tracks 911 Carrera, 911 Carrera S
Tire Rim Rim offset Track
Summer tires*front 235/40 ZR 18 (91Y) 8 J x 18 H2 57 mm 58.5 in./1486 mm
rear 265/40 ZR 18 (101Y) XL 10 J x 18 H2 58 mm 60.4 in./1534 mm
orfront 235/35 ZR 19 (87Y) 8 J x 19 H2 57 mm 58.5 in./1486 mm
rear 295/30 ZR 19 (100Y) XL 11 J x 19 H2 67 mm 59.7 in./1516 mm
orfront 235/35 ZR 19 (87Y) 8.5 J x 19 H2 55 mm 58.7 in./1490 mm
rear 305/30 ZR 19 (102Y) XL 11.5 J x 19 H2 67 mm 59.7 in./1516 mm
Snow tiresfront 235/40 R 18 91V M+S 8 J x 18 H2 57 mm 58.5 in./1486 mm
rear 265/40 R 18 97V M+S** 10 J x 18 H2 58 mm 60.4 in./1534 mm
orfront 235/35 R 19 87V M+S 8 J x 19 H2 57 mm 58.5 in./1486 mm
rear 295/30 R 19 100V XL M+S 11 J x 19 H2 67 mm 59.7 in./1516 mm
The load capacity coefficient (e.g. “91”) and maximum speed code letter (e.g. “Y”) are minimum requirements.
Snow chainsCan be mounted only on the rear wheels; maximum speed 30 mph (50 km/h).
Use only Porsche authorized fine-link cross-type or edge chains.
Snow chain clearance can be guaranteed only on the tire + rim combination marked** without spacers.
Tire and rim sizesExtensive tests are performed before specific tires and wheels are approved by Porsche. Your Porsche dealer has informa-
tion about approved tires and wheels and is happy to assist you.
If aftermarket tires and/or wheels are installed which are not approved by Porsche, the vehicle’s roadability and handling
characteristics might be impaired. Since Porsche has no data on such combinations, Porsche cannot stand behind the safe-
ty or durability of these aftermarket combinations.
* 911 Carrera S: Summer tires 19-inch only