PORSCHE 911 CARRERA 2005 5.G Repair Manual

Controls, Instruments
61
Brake booster The brake booster assists braking only when
the engine is running.
When the car is moving while the engine is not run-
ning, or if the brake booster is defective, more
pressure on the brake pedal is required to bring
the car to a stop.
Moisture or road salt on brakes affects braking.
When the vehicle is driven on salted roads for ex-
tended periods, the brakes should be washed
down thoroughly about every 2 weeks. An auto-
matic carwash facility cannot do this job properly.
Brakes will dry after a few cautious brake applica-
tions.
Warning!
Driving through water may reduce the trac-
tion.
Moisture on brakes from road water, car
wash, or coating of road salt may affect
braking efficiency.
fCautiously apply brakes to test brakes after being exposed.
Brake wear Your car has excellent brakes, but they are still
subject to wear. The rate at which they wear de-
pends on how the brakes are used.
fHave the brake system inspected at the
intervals recommended in your Maintenance
Booklet.
If the warning lights in the instrument panel and on-
board computer stay on when the engine is run-
ning or come on while driving, the brake pads are
worn, excessively.
fDo not continue to operate the vehicle.
Have your authorized Porsche dealer inspect
or replace the brake pads.
Brake pads Wear on the brake pads and brake discs depends
to a great extent on the driving style and the con-
ditions of use and therefore cannot be expressed
in actual miles on the road.
The high-performance brake system is designed
for optimal braking effect at all speeds and tem-
peratures.
Certain speeds, braking forces and ambient
conditions (such as temperature and humidity)
therefore might cause “brake noises”.
New brake pads or linings
New brake pads and brake discs have to be “bro-
ken in”, and therefore only attain optimal friction
when the car has covered several hundred miles
or km.
The slightly reduced braking ability must be com-
pensated for by pressing the brake pedal harder.
This also applies whenever the brake pads and
brake discs are replaced.
Warning light USA
Warning light Canada

62
Controls, Instruments
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 during normal driv-
ing, including panic braking in turns.
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.

Controls, Instruments
63
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

64
Controls, Instruments
Sport ModeA sportier car set-up is obtained when Sport mode
is switched on. Interventions by the Porsche
control systems are intentionally shifted towards
greater agility and driving performance.
– PASM (Porsche Active Suspension Manage-
ment) is automatically changed to Sport mode,
resulting in a stiffer suspension setup.
– The Tiptronic S switches to a sporty gear-
changing map and shortens the gear shifting
periods. Gear changes take place faster.
– PSM (Porsche Stability Management) control is
sporty. PSM interventions take place later than
in Normal mode. The driver can maneuver the
vehicle with greater agility at its performance
limits, without having to dispense with the
assistance of PSM in emergency situations.
– The electronic accelerator pedal reacts
sooner, and the engine is more responsive to
throttle inputs. When Sport mode is switched
on, this function is activated only after the
driver has floored the accelerator pedal or
released it briefly.
– The rpm limiter characteristic is “harder”, i.e.
the engine is immediately throttled when the
performance limits are reached (only in manual
selection mode for vehicles with Tiptronic S).
fPlease observe the appropriate chapters of
this Manual.
Switching Sport mode on and offfPress SPORT button in the center console.
When Sport mode is switched on, the light-
emitting diode in the SPORT button is lit.When Sport mode is switched on, the logo SPORT
appears next to the digital speedometer.
Switching Sport mode on and off simultaneously
activates and deactivates the Sport mode of the
PA S M .
If the Sport mode of the PASM was activated with
the PASM button, it will remain on.
After the ignition is switched off, Sport mode is
automatically reset to Normal mode.

Controls, Instruments
65
Porsche Stability Management
(PSM)PSM is an active control system for stabilization of
the vehicle during extreme driving manoeuvres.
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 PSM.
The risk of accidents due to inappropriate
speed cannot be reduced, even by PSM.
The driver bears the responsibility for all
driving maneuvers.
fAdapt your driving style to the prevailing road
and weather conditions.
fObey all traffic laws. Advantages of PSM – Superior traction and lane-holding ability in all
driving situations – even on road surfaces with
varying friction.
– PSM actively stabilizes the vehicle during dy-
namic driving maneuvers (e.g. rapid steering
movements, during lane changes or on alter-
nating curves).
– Improved braking stability in curves and on dif-
ferent or varying road surfaces.
Readiness for operationPSM is switched on automatically every time you
start the engine.FunctionSensors at the wheels, brakes, steering system
and engine continuously measure:
–Speed
–Steering angle
– Lateral acceleration
– Rate of turn about the vertical axis
– Brake pressure
PSM uses these values to determine the direction
of travel desired by the driver.
PSM intervenes and corrects the course if the
actual direction of motion deviates from the
desired course (steering-wheel position):
It brakes individual wheels as needed. In addition,
the engine power may be manipulated in order to
stabilize the vehicle.The events below inform the driver of PSM control
operations and warn him to adapt his driving style
to the road conditions:
– The multi-functional information light on the
instrument panel lights up.
– Hydraulic noises can be heard.
– The vehicle decelerates and steering-wheel
forces are altered as the PSM controls the
brakes.
– Reduced engine power.
– The brake pedal pulsates and its position is
changed during braking.
In order to achieve full vehicle deceleration,
foot pressure must be increased after begin-
ning the brake pedal pulsing.
f f f

66
Controls, Instruments Examples of PSM control operations
– If the front wheels of the vehicle drift on a
bend, the rear wheel on the inside of the bend
is braked and the engine power is reduced if
necessary.
– If the rear of the vehicle swings out on a bend,
the front wheel on the outside of the bend is
braked.
The PSM should always be switched on
during “normal” driving.
However, it may be advantageous to switch off
PSM temporarily in exceptional situations, for
example:
– On a loose surface or in deep snow,
– When “rocking the vehicle free” and
Switching off PSMfPress PSM OFF button.
PSM is switched off after a short delay.
The light-emitting diode in the button is illumi-
nated.
When the PSM is switched off, the multifunc-
tional PSM light on the instrument panel is lit
and a message is shown by the on-board
computer.
An acoustic signal also sounds.The following functions stabilize the vehicle in
emergency situations, even with PSM switched
off:
– When PSM is off, the vehicle is stabilized as
soon as one of the two front wheels enters the
ABS control range.
– When PSM is off and Sport mode is on, the
vehicle is stabilized as soon as both front
wheels enter the ABS control range.
One-sided spinning of the wheels is prevented,
even with PSM switched off.
Switching PSM back onfPress PSM OFF button.
PSM is switched on after a short delay.
The light-emitting diode in the button and the
multifunctional PSM light go out.
The on-board computer shows a message.

Controls, Instruments
67
Sport modeA sportier car set-up is obtained when Sport mode
is switched on. PSM interventions are later than in
Normal mode; the vehicle can be manoeuvred
with greater agility at its performance limits,
without the need to dispense with the assistance
of PSM in emergency situations. This helps to
achieve optimal lap times, particularly on race
circuits and a dry road surface. – The multifunctional light on the instrument
panel lights up for a lamp check when the
ignition is switched on.
– The light indicates a control operation by
flashing, including when PSM is switched off
(brake control in the event of one-sided wheel
spin).
– In conjunction with a message on the on-board
computer, the light indicates that PSM is
switched off.
An acoustic signal also sounds.
– Faults are displayed by the light in conjunction
with a message on the on-board computer.
PSM is out of order.
fPlease consult an authorized Porsche dealer.
fPlease observe the chapter “PUTTING
VEHICLE INTO OPERATION” on Page 239.
fPlease observe the chapter “WARNINGS ON
THE INSTRUMENT PANEL AND THE ON-
BOARD COMPUTER” on Page 105.
TowingfPlease observe the chapter “VEHICLE
TOWING” on Page 259.Checks on test standsWhen carrying out brake tests on roller test
stands a maximum testing speed of 5 mph
(8 km/h) must not be exceeded.
Handbrake checks on the roller brake tester
must be performed only with the ignition switched
off.
Multifunctional PSM light

68
Controls, Instruments The previously selected PASM mode is always ac-
tivated after the engine is started.
There is no automatic return to normal mode after
the ignition is switched off.
PASM makes two running-gear setups available to
the driver: “Normal” and “Sport”.
The selection is made via a button on the center
console.
In Normal mode the running gear is in a sporty and
comfortable setup.
Sport mode offers a markedly sporty shock
absorber tuning (e.g. for driving on the race
circuit).
The variable suspension system selects the appro-
priate damping level for each wheel according to
the situation and conditions of driving.
Example:
If the vehicle is driven in a markedly sporty manner
in Normal mode, PASM automatically adapts the
shock-absorber behavior to the driving situation in
this case as well.
Switching on PASM Sport modefPress PASM button in the center console.
When PASM Sport mode is switched on, the
light-emitting diode in the button is illuminated
and a message is shown by the on-board
computer.
Switching off PASM Sport modefPress PASM button in the center console.
The light-emitting diode in the button goes out
and the on-board computer displays a
message.
Porsche Active Suspension
Management (PASM)

Controls, Instruments
69
A, C - Switch for reading light on driver/passenger side
B- Switch for interior light and footwell lights
D- Orientation lightInterior LightsfPlease observe the chapter “LOAD SWITCH-
OFF AFTER 2 HOURS OR 7 DAYS” on
Page 233.
For vehicles with automatic anti-dazzle
mirrors
fSwitch off the automatic anti-dazzle operation
of the mirrors before you switch on the interior
light.
Otherwise the mirrors may accidentally swivel
into the anti-dazzle position.
Interior lights, reading lightsSwitching off
fPress left half of switch.
Switching to continuous illumination
fPress right half of switch.
Switching on and off automatically
fMove switch to center position.
The interior and footwell lights are switched
on when a door is unlocked or opened or when
the ignition key is withdrawn from the ignition
lock.
The lights are switched off with a delay of
approx. 2 minutes after the doors are closed.
The light goes out immediately as soon as the
ignition is switched on or the vehicle is locked.
Orientation lightA light-emitting diode at the bottom of the interior
mirror improves orientation in the passenger com-
partment when it is dark.
Note on operation
On vehicles with the Sport Chrono package, the
brightness of the orientation light can be changed
in PCM.
Please observe the chapter “Individual Memory” in
the separate PCM operating instructions.

70
Controls, Instruments
Operation, Instruments 1. Ignition lock/steering lock
2. Turn signals/high beam/headlight flasher stalk
3. Hands-free microphone for telephone
4. Horn
5. Wiper/washer stalk, rear window wiper
6. Button for seat heating, left
7. Interior temperature sensor/GPS antenna
8. Stopwatch
9. Emergency flasher switch
10.Central locking button, readiness display for
alarm system
11.Porsche Communication Management (PCM)12.Button for seat heating, right
13.Cupholder
14.Light switch
15.Operating lever for on-board computer
16.Locking lever for steering-wheel adjustment
17.Operating lever for automatic speed control
18.Operating panel for air conditioning
19 Buttons for rear spoiler,
Porsche Active Suspension Management
(PASM),
Sport mode, Porsche Stability Management
(PSM)