2009 PORSCHE 911 tires

Operation, Safety
63
Porsche Traction Management
(PTM)With PTM, the engine power is variably distributed
to the front and rear wheels.
Power distribution between the front and rear ax-
les is performed by a map-conrolled multiple-disc
clutch.
Distribution of the engine power also depends on
the difference in wheel speed between the two ax-
les.
The multiple-disc clutch always delivers sufficient
drive power to the front wheels to ensure optimum
propulsion even on an unfavorable road surface.
In combination with the Porsche Stability Manage-
ment (PSM), the PTM ensures optimum handling
and high driving stability.
Warning!
The increased control that is provided should
not induce you to take greater risks with your
safety. The limits dictated by the laws of phy-
sics cannot be overcome, even with PTM.
The risk of accidents due to inappropriate
speed cannot be reduced, even by PTM.
The driver bears the responsibility for all dri-
ving maneuvers.
fAdapt your driving style to the prevailing road
and weather conditions.
fObey all traffic laws.
Dynamometer testing procedure Some U.S. states and Canadian provinces con-
duct emissions inspection/maintenance testing in-
volving the use of two-wheel dynamometer.
A two-wheeled dynamometer is a treadmill type
device upon which a single axle of the car, the dri-
ving axle of the vehicle, rotates to simulate vehicle
operation on the road while the vehicle remains
stationary.
Your vehicle has a full-time four-wheel drive system
which cannot be disabled. Severe damage to the
powertrain can result if tested on a two-wheel dy-
namometer.
Warning!
Risk of severe powertrain damage and a pos-
sible unexpected movement of the vehicle.
fDo not test your vehicle on a two-wheel dyna-
mometer.
fAdvise the emission station of this warning be-fore testing the vehicle.
Brake testsBrake tests must be performed only on plate-type
test stands or roller test stands.
The ignition must be off.
The following limit values must not be exceeded
on roller test stands:
– Testing speed 5 mph (8 km/h)
– Test duration 20 seconds Handbrake tests Handbrake tests on the roller test stand must only
be carried out with the ignition switched off. Balancing wheels on the vehicle During finish balancing of the wheels, the vehicle
must be hoisted and all the wheels able to rotate
freely. Towing fPlease see the chapter “TOWING” on
Page 280.Wheels/TiresThe PTM control unit is adapted to the approved
tire sizes. The use of non-approved tire sizes may
lead to deviations in wheel speeds and it may influ-
ence handling or result in the PTM switching off.

98
Operation, Safety
Porsche Communication
Management (PCM) fRefer to the separate operating instructions
before putting the PCM into operation.
fPlease see the chapter “LOAD SWITCH-OFF
AFTER 2 HOURS OR 7 DAYS” on Page 258.
Warning!
There is a danger of accident if you set or
operate the on-board computer, radio, navi-
gation system, telephone or other equipment
when driving.
This could distract you from the traffic and
cause you to lose control of the vehicle re-
sulting in serious personal injury or death.
fOperate the components while driving only if
the traffic situation allows you to do so safely.
fCarry out any complicated operating or setting procedures only with the vehicle stationary.
The reception conditions for the radio module
integrated in the PCM change continuously as you
drive. Interference from buildings, terrain and the
weather is unavoidable.
FM stereo reception is particularly susceptible to
varying reception conditions.
Electronic accessories should only be retrofitted
by your authorized Porsche dealer.Accessories which have not been tested and
approved by Porsche may impair radio function
and reception.
NavigationWhen put into operation for the first time, a
distance of approx. 30 miles (50 km) must be
driven in order for the navigation system to
complete the process of fine calibration.
The same applies when the tires are changed (e.g.
summer/snow tires) or new tires fitted.
Full location accuracy is not yet achieved during
the fine-calibration process.
If the vehicle has been transported (e.g. ferry, car
train), the system may take a few minutes to deter-
mine the current location after it has been
switched on.
Serious tire slip (e.g. spinning wheels on snow)
may result in temporarily inaccurate navigation.
When the battery has been disconnected, it may
take up to 15 minutes before the navigation
system is operational again.
Car Audio Operation/Tips For radio operation see your radio manual
which is included with your on-board litera-
ture.
fPlease see the chapter “LOAD SWITCH-OFF AF-
TER 2 HOURS OR 7 DAYS” on Page 258.
FM reception
A vehicle is not an ideal place to listen to a radio.
Because the vehicle moves, reception conditions
are constantly changing.
Buildings, terrain, signal distance and noise from
other vehicles are all working against good recep-
tion.
Some conditions affecting FM may appear to be
problems when they are not.
The following characteristics are completely nor-
mal for a given reception area, and they do not in-
dicate any problem with the radio itself.
Note
Electronic accessories should only be installed by
your authorized Porsche dealer.
Equipment which has not been tested and ap-
proved by Porsche may impair radio reception.

Instruments, On-Board Computer, Warnings
143
TPM
Tire Pressure MonitoringfPlease see the chapter “TIRE PRESSURES FOR
COLD TIRES (68 °F / 20 °C)” on Page 289.
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.
Warning!
fDespite the advantages offered by the Tire
Pressure Monitoring, it is still the driver’s re-
sponsibility to update the corresponding set-
tings 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 a fault occurs in the Tire Pressure Monitoring
(e.g. defective wheel transmitter), contact an
authorized Porsche dealer immediately and
have the damage repaired.
The tire pressure will not be monitored at all or
will be monitored only partially by 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 Mnitoring cannot warn you
about tire damage that occurs suddenly (e.g.
flat tire due to abrupt external effects).

Instruments, On-Board Computer, Warnings
145
The tire pressure to be corrected (refill pressure)
is indicated on the displayed wheel.
Example: If “ –1.5 psi (–0.1 bar)” is displayed,
1.5 psi (0.1 bar) must be added to this tire.
Note
The tire pressure menu can only be called up when
the vehicle is stationary.
Calling up the “Info pressure” display
fPush operating lever forward in order to switch
on the selection field.
fSelect “TPM” with the operating lever.
fPush operating lever forward.
The display changes to the tire pressure menu.
fSelect “Info pressure” with the operating lever.
fPush operating lever forward.
Note
After the ignition is switched on, it can take up to
approx. 1 minute before all tire pressures are
displayed. Dashes (“-.-”) appear instead of the tire
pressures. 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 “TPM” 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 “TPM” with the operating lever.

148
Instruments, On-Board Computer, Warnings The tire selection 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 see the chapter “SYSTEM LEARNING”
on Page 150.
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.
fPlease consult your authorized Porsche
dealer.
fUse only tires approved by Porsche.
The available items in the tire pressure menu
depend on the tires on 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.
fMake sure that tire pressures correspond to
the on-board computer settings. Correct the
tire pressure if necessary.
fPlease see the chapter “TIRE PRESSURES FOR
COLD TIRES (68 °F / 20 °C)” on Page 289.Load
fPush operating lever forward in order to switch
on the selection field.
fSelect “TPM” with the operating lever.
fPush operating lever forward.
The display changes to the tire pressure menu.
fSelect “Load” with the operating lever.

Instruments, On-Board Computer, Warnings
149
fSelect partial load or full load and push the
operating lever forward.
fPlease see the chapter “TIRE PRESSURES FOR
COLD TIRES (68 °F / 20 °C)” on Page 289.
fMake sure that the tire pressures correspond
to the on-board computer settings. Correct the
tire pressures if necessary.Tire pressure warnings
The tire pressure warning light on the instrument
panel and a corresponding message on the on-
board computer warn about loss of pressure in
two stages, depending on the amount of pressure
loss.
Driving with insufficient tire pressure reduces the
road safety of the vehicle and destroys the tire and
wheel.
Stage 1 – Add air
The pressure in the tire is too low by 4 to 7 psi (0.3
to 0.5 bar).
fThe tire pressure warning contains the
affected tire with the tire pressure to be added.
Correct the tire pressure at the next
opportunity. This tire pressure warning appears
– for approx. 10 seconds with vehicle stopped
when switching off the ignition or
– again when switching on the ignition.
With ignition on, the warning can be deactivated.
The tire pressure warning light in the instrument
panel goes out only when the tire pressure has
been corrected.

150
Instruments, On-Board Computer, Warnings Stage 2 – Flat tire
At speeds below 100 mph (160 km/h):
The pressure in the tire has dropped by more
than 7 psi (0.5 bar). This significant pressure
loss is a danger to road safety.
At speeds above 100 mph (160 km/h):
The pressure in the tire has dropped by more
than 5 psi (0.4 bar). This significant pressure
loss is a danger to road safety.
fWhen the tire pressure warning appears, stop
immediately at a suitable location. Check the
indicated tire for signs of damage. If neces-
sary, fill in tire sealant and set the correct tire
pressure.This tire pressure warning also appears when
driving and can be acknowledged.
The tire pressure warning light on the instrument
panel goes out only when the tire pressure has
been corrected.
System learningThe Tire Pressure Monitoring begins to “learn” the
wheels after a wheel change, wheel transmitter
replacement or update of the tire settings. During
this process, the Tire Pressure Monitoring recog-
nizes the tires and their locations.
The on-board computer displayes the message
“TPM is learning, monitoring not act.”.
The Tire Pressure Monitoring requires a certain
amount of time to learn the wheels. During this
time, the current tire pressures are not available
on the on-board-computer:
– The tire pressure warning light remains lit until
all wheels have been learned.
– The display of the tire pressure function of the
on-board computer shows lines.
– The required pressures for cold tires at 68 °F
(20 °C) are indicated in the Info pressure
display in the tire pressure menu.
Position and pressure information is displayed as
soon as the Tire Pressure Monitoring has as-
signed the wheels identified as belonging to the
vehicle to the correct wheel positions.
The wheel learning process takes place
exclusively when the vehicle is being driven
(vehicle speed above 25 km/h (16 mph)).
fCheck the tire pressure for all wheels on the
“Info pressure” display.
fCorrect the tire pressure to the required
pressure if necessary.

Instruments, On-Board Computer, Warnings
151
Changing a wheel and replacing tiresfNew wheels must be fitted with radio transmit-
ters for the Tire Pressure Monitoring.
Before tires are changed, the battery charge
state of the wheel transmitters should be
checked at an authorized Porsche dealer.
fSwitch the ignition off when changing a wheel.
The tire settings on the on-board computer must
be updated after changing a wheel.
If the tire settings are not updated, the message
“Wheel change? Input new TPM settings!” is
displayed on the on-board computer.
fUpdate the on-board computer settings when
the vehicle is stationary the next time.
Warning!
Your vehicle has also been equipped with a Tire
Pressure Monitoring (TPM) malfunction indicator
when the system is not operating properly.
The TPM malfunction indicator is combined with a
low tire pressure telltale.
When the system detects a malfunction, the tellta-
le will flash for approx. one minute and then remain
continuously illuminated. This sequence will conti-
nue upon subsequent vehicle start-ups as long as
the malfunction exists.
When the malfunction indicator is illuminated, the
system may not be able to detect or signal low tire
pressure as intended.
TPM malfuntions may occur for a variety of
reasons, including the installation of replacement
or alternate tires or wheels on the vehicle that
prevent the TPM from functioning properly.
Always check the TPM malfunction telltale after
replacing one or more tires or wheels on your
vehicle to ensure that the replacement or alter-
nate tires and wheels allow the TPM to continue to
function properly.The warning light in the speedometer lights up:
– When a loss in pressure has been detected.
– When learning newly mounted wheels/wheel
sensors, as long as the vehicle’s own wheels
have not yet been recognized.
In the event of a defect in Tire Pressure Monitoring
or a temporary fault, the warning light in the
speedometer flashes for approx. one minute and
then remains continuously illuminated.
The tire pressure warning light in the instrument
panel goes out only when the cause of the fault
has been rectified.
Partial monitoringMonitoring of the other wheels is continued if there
is a fault in one or two wheel transmitters.
– The tire pressure warning light lights up.
– The message “TPM partial monitoring” is
displayed on the on-board computer.
– No tire pressures are displayed on the on-
board computer for wheels with faulty wheel
transmitters.
Warning light