2009 PORSCHE 911 tire pressure monitoring

Operation, Safety
61
ABS Brake System
(Antilock Brake System)The ABS system represents a major contribution
to the enhancement of active safety in your vehi-
cle. This system prevents the wheels from locking
in a panic stop on almost all road surfaces.
With the ABS system in your vehicle, the
following areas are enhanced:
Steering, vehicle remains steerable under all
braking forces when ABS is engaged.
Good directional control, no swerving caused
by locking of wheels under braking conditions.
Shorter stopping distance, stopping distances
are usually reduced because controlled braking is
maximized.
Prevention of wheel lock up, no brake- induced
sliding and thus no localized tire wear from emer-
gency braking.
The crucial advantage of the ABS system over a
conventional brake system is in the area of main-
taining directional control and maneuverability of
the car in emergency situations.
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
physics cannot be overcome, even with ABS.
The risk of accidents due to inappropriate
speed cannot be reduced, even by the ABS.
The driver bears the responsibility for all
driving maneuvers.
fAdapt your driving style to the prevailing road
and weather conditions.
fObey all traffic laws.
Other vehicles not equipped with the ABS
system may not be able to maintain control,
especially on wet or poor road surfaces and
thus may be more likely to impact you from
behind.
fTo minimize that risk, use your ABS system to
increase your ability to maneuver to avoid dan-
gerous situations and not merely to try to stop in the shortest distance possible.
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.
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 au-
dible 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.
fIf full braking should be necessary, press the
brake pedal all the way down throughout the
entire braking procedure, regardless of the pul-
sating pedal. Do not ease up on pressure ap-
plied to the pedal.
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.

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).

144
Instruments, On-Board Computer, Warnings Tire pressure function of the on-board
computer
The tire pressure function of the on-board
computer displays the tire pressures (actual
pressure) dependent on temperature in the four
wheels.
You can watch the tire pressure rise as the
temperature increases while driving.
This display is only for information.
fUnder no circumstances should the tire
pressures be changed based on this display.
Warning!
This display is for informational purposes
only. Under no circumstances should the tire
pressures be changed based on this display.
Changing the tire pressure to incorrect
pressures could adversely affect the perfor-
mance, driving characteristics, and safety of
your vehicle.
fMaintain tire pressures according to the units
indicated on the tire pressure plate, located on the drivers side door of the vehicle.
Displaying the tire pressure function of the
on-board computer
fPush operating lever up or down until the tire
pressure function of the on-board computer
appears.
(The selection field must be switched off.)Pressure info in tire pressure menu
In accordance with physical principles, the air
pressure changes as the temperature changes.
The tire pressure increases or decreases by
around 1.5 psi (0.1 bar) for every 18 °F (10 °C)
change in temperature.
The Tire Pressure Monitoring takes this relation-
ship between tire pressure and temperature into
account.
fPlease see the chapter “PRESSURE INCREASE
AS THE RESULT OF TEMPERATURE
INCREASE” on Page 152.
You can read the tire pressures to be
corrected in this display.

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.

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

152
Instruments, On-Board Computer, Warnings
No monitoringIn the event of faults the Tire Pressure Monitoring
cannot monitor the tire pressure.
The warning light in the speedometer flashes for
approx. one minute and then remains continuously
illuminated and a corresponding message
appears on the on-board computer.
Monitoring is not active when:
– the Tire Pressure Monitoring is faulty,
– wheel transmitters for the Tire Pressure
Monitoring are missing,
– during the learning phase after the tire settings
have been updated,
– after a wheel change without updating the tire
settings,
– more than four wheel transmitters are
detected,
– there is external interference by other radio
sources, e.g. wireless headphones,
– tire temperatures are too high.
fPlease see the chapter “WARNINGS ON THE
INSTRUMENT PANEL AND THE ON-BOARD
COMPUTER” on Page 158.
Pressure increase as the result of
temperature increaseIn accordance with physical principles, the air
pressure changes as the temperature changes.
The tire pressure increases or decreases by
around 1.5 psi (0.1 bar) for every 18 °F (10 °C)
change in temperature.
The Tire Pressure Monitoring takes this relation-
ship between tire pressure and temperature into
account.Tire pressure specificationsInformation on tire pressure for public roads can
be found in this Owner's Manual in the Technical
Data chapter or on the tire-pressure plate in the
left door aperture.
These values apply to cold tires at 68 °F (20 °C)
ambient temperature.

Warnings
165
Rear lid
not closedThe convertible top cannot be operated with the
rear lid open.
Flat tyre! Tire Pressure Monitoring has detected a serious
pressure loss.
Stop at a suitable place and check tires for dam-
age. Fill in tire sealant if necessary.
Add air The Tire Pressure Monitoring has detected a
gradual pressure loss. Correct tire pressure at
the next opportunity.
TPM is learning
monitoring
not act.The Tire Pressure Monitoring is learning the
wheels on the vehicle. The Tire Pressure Moni-
toring is searching for the tires and their posi-
tion. During this period the current pressure
specifications are not available on the on-board
computer.
TPM inactive The Tire Pressure Monitoring is faulty.
Consult an authorized Porsche dealer.
TPM partial monitoring 1 or 2 wheel transmitters are faulty. The tyre
pressures of these wheels are not monitored.
The other wheels are still monitored.
Consult an authorized Porsche dealer.
TPM inactive
Brief disturbance
TPM inactive
Too many wheel transmittersThe Tire Pressure Monitoring is temporarily de-
activated by excessive tire temperatures (ap-
prox. 248 °F (120 °C)) or external interference
(e.g. from other wheel transmitters inside the
car). Once the source of the interference is re-
moved, the system is automatically reactivated.
Wheel change?
Input new
TPM settings!Update the settings in the TPM menu of the
on-board computer at the next opportunity.
Wrong entries will affect the correct pressure in-
formation in the menu. The safety of your vehi-
cle is at risk.
Instrument
panelOn-board
computerText display on on-board
computerMeaning/measure