wheel torque AUDI A4 2008 B8 / 4.G Owners Manual

Intelligent technology 222Intelligent technologyElectronic stabilisation program (ESP)DescriptionESP increases the car's stability. It reduces the tendency to skid and
improves the stability and roadholding of the vehicle. ESP detects
critical handling situations, such as understeer, oversteer and
wheelspin on the driven wheels. It stabilises the vehicle by braking
individual wheels or by reducing the engine torque. The warning
lamp
 in the instrument cluster starts flashing as soon as the ESP
intervenes.
The ESP incorporates the functions of the anti-lock brake system
(ABS), the traction control system (ASR), the electronic differential
lock (EDL) and the dynamic steering*.
Anti-lock brake system (ABS)
ABS prevents the wheels from locking up under braking until the
vehicle has reached a virtual standstill. You can continue to steer the
vehicle even when the brakes are on full. Keep your foot on the brake
pedal and do not pump the brakes. You will feel the brake pedal
pulsate while the anti-lock brake system is working.
Brake assist system
The brake assist system can speed up the braking process and
shorten the braking distance. It automatically boosts the braking
force if you press the brake pedal quickly in an emergency. On vehi-
cles with adaptive cruise control*, the brake assist system will build
up a small amount of pressure in the hydraulic brake system if it
senses that you are too close to the vehicle in front.
Traction control system (ASR)
In the event of wheelspin, the traction control system reduces the
engine torque to match the amount of grip available. This helps the
car to start moving, accelerate or climb a gradient.Electronic differential lock (EDL)
When the EDL detects wheelspin, it brakes the spinning wheel and
directs the power to the other driven wheel (or wheels on quattro*
versions). This function is active up to about 100 km/h.
To prevent the disc brake of the braked wheel from overheating, the
EDL cuts out automatically if subjected to excessive loads. The
vehicle can still be driven. The EDL will switch on again automati-
cally when the brake has cooled down.
Dynamic steering*
On vehicles with dynamic steering*, the ESP can also intervene in
the steering to stabilise the vehicle in critical situations.
WARNING
•
The grip provided by the ESP, ABS, ASR, EDL and dynamic
steering* systems is still subject to the physical limits of adhesion.
Always bear this in mind, especially on wet or slippery roads. If
you notice the systems cutting in, you should reduce your speed
immediately to suit the road and traffic conditions. Do not let the
extra safety provided tempt you into taking any risks when driving
– this can cause accidents.
•
Please remember that the accident risk always increases if you
drive fast, especially in corners or on a slippery road, or if you
follow too close behind the vehicle in front of you. Please bear in
mind that even ESP, ABS, brake assist, EDL, ASR and dynamic
steering* cannot compensate for the increased accident risk.
•
When accelerating on a uniformly slippery surface (for instance
all four wheels on ice or snow), press the accelerator gradually and
carefully. The driven wheels may otherwise start to spin (in spite
of the integrated control systems), which would impair the car's
stability and could lead to an accident.
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Self-help 284If you need the tools, the Tyre Mobility System or the jack*, you will
have to open the floor panel and take out the spare wheel*
⇒page 284.
The tool kit includes:•
A hook for removing hub caps
•
Pin for mounting a wheel
•
Screwdriver with reversible blade
•
Tool for changing bulbs
•
Interchangeable socket (Torx socket for changing bulbs)
•
Crank handle for jack
•
Adapter for anti-theft wheel bolts*
•
Jack*
•
Box spanner for wheel bolts
•
Towline anchorage
Some of the parts listed are only fitted on certain models or are
optional extras.
Before stowing the jack* again, wind down the arm of the jack as far
as it will go.
WARNING
•
Do not use the hexagonal socket in the screwdriver handle to
tighten the wheel bolts. It is not possible to tighten the bolts with
the required torque – risk of accident.
•
The jack supplied by the factory is only designed for changing
wheels on this model. On no account attempt to use it for lifting
heavier vehicles or other loads – risk of injury.
•
Never start the engine when the vehicle is on the jack - risk of
accident.
•
If work has to be done under the veh i cl e , e n su re t h a t i t is sa fe l y
supported on stands designed for the purpose, otherwise there is
a risk of injury.
Applies to vehicles: with compact temporary spare wheelCompact temporary spare wheel*The spare wheel is carried in the wheel well under the
floor panel in the luggage compartment. It is only
intended for temporary use over short distances.Taking out the spare wheel
– Lift the floor panel by the plastic handle ⇒fig. 268.
– Hook the handle onto the luggage compartment weath-
erstrip.
– Turn the centre plastic knob ⇒fig. 268 anti-clockwise.
– Take out the spare wheel.
– Unhook the floor panel before closing the boot lid.
Securing the defective wheel in the spare wheel
well
– Place the wheel in the spare wheel well and secure it with
the plastic knob.
– Unhook the floor panel before closing the boot lid.
Fig. 268 Spare wheel
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Self-help289
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
–Loosen the wheel bolts ⇒page 289.
–Raise the car with the jack* ⇒page 290.
–Ta k e o f f the wheel with the flat tyre and then put on the
spare wheel* ⇒page 291.
–Lower the vehicle to the ground.
– Tighten the wheel bolts firmly i n d i a g o n a l s e qu e n c e w i t h
the box spanner ⇒page 289.
–Fit the hub cap back on.After changing a wheel
What you must do after changing a wheel.– Place the wheel with the defective tyre in the spare wheel
well and secure it.
– Put the tools and the jack* back in the luggage compart-
ment.
–The inflation pressure of the newly fitted spare tyre must
be checked as soon as possible.
–Have the tightening torque of the wheel bolts checked as
soon as possible with a torque wrench. The correct tight-
ening torque is 120 Nm.
– Have the flat tyre replaced as quickly as possible.
Note•
If you notice that the wheel bolts are corroded and difficult to
turn when changing a wheel, they must be replaced before having
the tightening torque checked.
•
In the interest of safety, drive at moderate speeds until the tight-
ening torque of the wheel bolts has been checked.
Hub caps
The hub caps must be removed for access to the wheel
bolts.Removing
– Insert the hook (provided in the vehicle's tool kit) in the
hole in the hub cap.
–Pull off the hub cap ⇒fig. 271.Loosening and tightening the wheel bolts
The wheel bolts must be loosened before raising the
vehicle.
Fig. 271 Changing a
wheel: Removing a hub
capFig. 272 Changing a
wheel: Loosening
wheel bolts
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