2008 AUDI A4 brake sensor

Driver information system35
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
5 seconds, but you can call it up again at any time by
pressing the button:
Ignition lock defective. Contact workshop!
–Do not switch off the engine.
– Drive the vehicle without delay to a qualified workshop
and have the fault repaired.The ignition cannot be switched off if there is a fault in the elec-
tronic ignition lock. For this reason, you should drive the vehicle
without delay to a qualified workshop and have the cause of the
fault repaired.
If the vehicle is equipped with the advanced key* feature, you
should not switch off the engine with the Stop/Start button because
it cannot be started again after the ignition has been switched off.
Note
On some models the symbol may look slightly different.Yellow symbols
A yellow symbol indicates a malfunction or other item
requiring attention.
Yellow symbols indicate a Priority 2 fault.
Yellow symbols are accompanied by one warning chime. The
symbol is accompanied by a driver message giving you more infor-
mation about the fault. This message will disappear after about
5 seconds, but you can call it up again at any time by pressing the
button.
The function indicated should be checked as soon as possible. The
yellow symbol will only go out when the fault has been rectified.
If several Priority 2 faults are detected at the same time, the symbols
are displayed one after the other for about 2 seconds at a time.
SET
Fig. 26 Display: Yellow
warning symbol

Dynamic steering
⇒page 36 and
⇒page 159

Brake pads worn
⇒page 37

Battery power*
⇒page 38

Bulb monitor*
Bulb failure*
⇒page 37

Check engine oil level
⇒page 38 or
⇒page 38

Engine oil sensor defective
⇒page 38

Fuel level low
⇒page 37

Washer fluid level low*
⇒page 37

advanced key*
Key not in vehicle
⇒page 36

Light sensor/rain sensor defec-
tive
⇒page 37

Diesel particulate filter*
obstructed
⇒page 38
SET
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Driver information system37
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Light sensor / rain sensor defective

 Automatic headlights / automatic wipers defective
If the  symbol appears, this means that the light sensor / rain
sensor is not functioning.For safety reasons, the dipped beam head-
lights will then be switched on permanently when the light switch
is set to the AUTO position. However, you can still switch the lights
on and off in the normal way with the light switch. If the rain sensor
is defective, the functions operated via the windscreen wiper lever
will still be available. You should have the light sensor / rain sensor
checked by a qualified workshop as soon as possible.
Brake pads worn

 Brake pads!
If the  symbol lights up, have the front brake pads (and, for
safety's sake the rear pads as well) inspected by a qualified
workshop.
Applies to vehicles: with bulb monitorBulb monitor

The bulb monitor checks whether the lights on the vehicle
are working.The bulb monitor checks whether the lights on the vehicle are
working. If it detects a defective bulb on the vehicle it will show a
yellow warning symbol together with a message indicating which
light is not working.
Bulb failure

If the symbol
 lights up, this means that one of the turn signals
(front or rear), headlights, brake lights, rear lights, fog lights or the
rear fog light is not working.
WARNING
•
Bulbs are sensitive to pressure. The glass can break when you
touch the bulb, causing injury.
•
Incorrect handling of the high-voltage element of xenon gas-
discharge bulbs* can have potentially fatal consequences.Note
Have the components repaired or replaced by a qualified
workshop.Applies to vehicles: with washer fluid warning systemWasher fluid level low

 Please top up washer fluid
If the  symbol lights up, top up the fluid for the windscreen
washer and headlight washer system* ⇒page 267.
Fuel level low

 Please refuel
When this symbol
 comes on for the first time, there are about
8 litres of fuel left in the tank. You should fill up as soon as possible
⇒page 252.
If this warning symbol lights up although the fuel tank is sufficiently
filled, there is a malfunction in the fuel tank system. The display will
also show the driver message Tank system malfunction ! Contact
workshop. Please contact a qualified workshop.
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adaptive cruise control (ACC)129
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
•
Adaptive cruise control will not react when approaching a
stationary obstacle, e.g. the end of a traffic jam or a broken-down
vehicle, or if a vehicle should come towards you in the same lane.
•
Please make sure you do not unintentionally rest your foot on
the accelerator - this will override the adaptive cruise control
system which, as a result, will not automatically brake the vehicle.Note
•
For safety reasons, the speed setting will be deleted when the
ignition is switched off.
•
Switching on the adaptive cruise control automatically activates
the Electronic Stabilisation Program (ESP) and the traction control
system (ASR). These two systems cannot be deactivated while the
adaptive cruise control is switched on.
•
Damage caused by impacts (e.g. if the vehicle is damaged when
parking) can affect the radar sensor settings. This can cause the
system to malfunction or switch off completely.
•
The radar sensor is heated. However, in winter conditions, you
should make sure that the radar sensor is free of ice and snow
before you set off. If necessary, carefully clean the cover of the radar
sensor and the surrounding area ⇒page 128, fig. 136.
•
To make sure that the radar sensor is fully operative, do not
attach any objects (e.g. stickers, add-on parts or other accessories)
to the area surrounding the radar sensor. Do not paint the area
surrounding the radar sensor.
Applies to vehicles: with adaptive cruise control and manual gearboxVehicles with manual gearbox
The driver of a vehicle with a manual gearbox of course
has to change gears as appropriate, even when the adap-
tive cruise control is activated.The adaptive cruise control is available from the second to the sixth
gear (when driven in normal engine speed range).
When the adaptive cruise control is activated, the driver must press
the clutch pedal as normal in order to change gear. When changing
gear or pressing the clutch pedal (for up to 20 seconds), the adap-
tive cruise control will remain activated.
When changing gear, the driver does not have to accelerate after
engaging a gear as the engine torque will be coordinated by the
adaptive cruise control.
The following situations may lead to an automatic deactivation of
the adaptive cruise control:•
pressing the clutch pedal too long (longer than approx.
20 seconds)
•
incorrect changing of gears and/or use of the clutch pedalNote
•
The adaptive cruise control cannot be activated while changing
gears.
WARNING (continued)
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adaptive cruise control (ACC) 130Applies to vehicles: with adaptive cruise controlHow does the distance control work?
Vehicles in front are detected by a radar sensor.The adaptive cruise control uses a radar sensor ⇒fig. 137 which is
integrated in the front of the vehicle and is subject to certain system
limitations ⇒page 140. Stationary objects are disregarded. The
system requires reflecting surfaces in order to be able to measure
the distance. If the ACC is unable to measure the distance it will not
respond.
No vehicle in front
When there is no vehicle in front, the adaptive cruise control works
like a speed control system. It maintains a constant target speed
specified by the driver.
Vehicle in front
If you catch up with a vehicle driving in front, the adaptive cruise
control will reduce the speed accordingly (within the limits set by
the system ⇒page 138, “Driver intervention prompt” and
⇒page 140, “System limitations”) and adapt it to the speed of the
vehicle in front. Then the system will try to adjust the distance to the
car in front according to the settings selected. During the adjust-
ment process the system may temporarily not be able to adhere to
the distance you had specified ⇒ in “Description” on page 128.If the vehicle in front accelerates, the adaptive cruise control will
also accelerate, up to the target speed you have specified.
Driver intervention prompt
In some situations, it is necessary for the driver to brake the vehicle
with the foot brake in order to keep a safe distance to the vehicle in
front or to avoid a collision. In this case, a warning message will
appear in the display and you will also hear a warning tone
⇒page 138.
When overtaking
When you move into the overtaking lane and no vehicle is detected
in front, the adaptive cruise control will accelerate up to the target
speed and then maintain it.
Overriding
You can still use the accelerator pedal at any time to increase speed
in the normal way. The previously programmed speed will be
resumed when the accelerator pedal is released.
Note
•
Please note that acceleration will vary depending on the preset
programme. If you have, for example, selected “Distance 1” and the
driving programme “dynamic”, acceleration will be more "sporty".
However, if you have set the system to “Distance 4” and driving
programme “comfort”, acceleration will be more gradual. For a
detailed description please refer to ⇒page 133, “Setting the
distance”.
•
No vehicle in front, Vehicle in front and a Driver intervention
prompt will be indicated by an indicator lamp ⇒page 134, “Indi-
cator lamp and display in the speedometer”.
Fig. 137 Area covered
by radar sensor
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adaptive cruise control (ACC)137
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
•
The control lever has been pushed up / down to increase / reduce
the speed, but the resulting speed would be outside the range of 30
to 200 km/h.
ACC deactivation
The message ACC deactivation sometimes appears on vehicles with
a manual gearbox. If you press the clutch pedal for longer than
about 20 seconds, the adaptive cruise control will be automatically
deactivated and a warning tone will sound.
ACC not available
The text message ACC not available will appear if, for example, the
brakes are overheated. The adaptive cruise control will then tempo-
rarily not be available. This is indicated by a warning tone.
ACC not available!
The text message ACC not available! appears if a malfunction
should occur. The adaptive cruise control will then be switched off.
This is indicated by a warning tone. Have the system checked by a
qualified workshop.
ACC sensor blocked!
The text message ACC sensor blocked! appears if the ACC system
can no longer detect objects reliably. The adaptive cruise control
will then be switched off. This is indicated by a warning tone.
The ACC sensor is obstructed by dirt or foreign objects (e.g. leaves
or snow). Clean the sensor to restore the function ⇒page 128,
fig. 136.
Engine speed !
On vehicles with manual gearbox, the text message Engine speed !
will appear if the driver does not change gear in time when the
adaptive cruise control accelerates or brakes the vehicle. The adap-
tive cruise control will automatically be deactivated if the engine
speed is not maintained within the permissible range. This is indi-
cated by a warning tone.ESP activation
The text message ESP activation appears if the Electronic Stabilisa-
tion Programme (ESP) has intervened. In this case, the adaptive
cruise control will automatically be switched off. This is indicated by
a warning tone.
Speed (in km/h)
The target speed (in km/h) will appear in the display whenever it is
stored or changed ⇒page 131, “Setting the speed” and
⇒page 131, “Setting a new speed”.
Speed range
The text message speed range appears if the current speed is too
low to set or to maintain the target speed.
To set a target speed, the speed of the vehicle must be at least
30 km/h. The cruise control system switches off if the speed falls
below 20 km/h.
If the speed exceeds 200 km/h (OVERRIDE), the system will remain
active and will reduce the speed to 200 km/h once the driver stops
accelerating.
ACC functionality limited
The text message ACC functionality limited appears if the ACC
system does not detect any objects for an extended period. The
distance to vehicles in front is not being controlled while the
message is displayed. The ACC system is not deactivated, and so
extra care should be taken! The text message ACC functionality
limited can appear for the following reasons:
•
The ACC sensor is dirty. The ACC system is not responding or is
not responding correctly to the vehicles in front!
•
You may be driving on a country road with no traffic and no clear
roadside demarcation (e.g. safety barriers, traffic signs, trees). As
soon as the system detects a vehicle, distance control is resumed
and the text message disappears.
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adaptive cruise control (ACC) 138The ACC sensor is located inside the trim grille (front right)
⇒page 128, fig. 136. If the sensor is no longer functioning due to
dirt or obstruction in this area, it should be cleaned.
Parking brake !
The text message Parking brake ! appears if the parking brake is
operated. The adaptive cruise control will then be switched off. This
is indicated by a warning tone.
Gear lever position !
On vehicles with manual gearbox the text message Gear lever
position ! appears when no valid forward gear is selected, i.e.
reverse gear or 1st gear is engaged or the gear lever is in the neutral
position. Adaptive cruise control is not available when the lever is in
these positions.
Shift lever position!
On vehicles with automatic gearbox the text message Shift lever
position ! appears if the shift lever is moved to position N. Adaptive
cruise control is not available when the lever is in this position.
Applies to vehicles: with adaptive cruise controlDriver intervention prompt
The driver intervention prompt is a warning for the driver
to reduce speed manually.Fig. 147 Instrument cluster: Driver intervention promptIn some situations the adaptive cruise control system alone is not
able to brake the vehicle sufficiently to maintain a safe distance to
the vehicle in front. The adaptive cruise control system will then call
on you as the driver to take control of the situation yourself.
The Driver intervention prompt provides both a visual and an
acoustic warning.•
A red vehicle symbol will appear in the instrument cluster
display ⇒fig. 147.
•
The system status indicator will show DISTANCE!.
•
The red warning lamp will start to flash.
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adaptive cruise control (ACC)141
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data Driving into a bend
When you are driving into a bend, the ACC system may react to a
vehicle travelling in the other lane and therefore brake the vehicle
⇒page 140, fig. 149. You can override the braking effect by pressing
the accelerator.
Driving out of a bend
When you are driving out of a long bend, the ACC system may - in
the course of its calculation of the lane ahead - react to a vehicle
travelling in the other lane and therefore brake the vehicle
⇒page 140, fig. 150. You can override the braking effect by pressing
the accelerator.
Applies to vehicles: with adaptive cruise controlVehicles in front travelling out of lineVehicles in front which are not in line with your vehicle cannot be
detected by the ACC system until they are within the range of the
sensor.
Applies to vehicles: with adaptive cruise controlOther vehicles changing lanesVehicles which are very close to you when they move onto your lane
cannot be detected by the radar sensor until they move into its
range.Applies to vehicles: with adaptive cruise controlNot clearly discernible vehiclesVehicles that are not clearly discernible, e.g. a motorcycle travelling
in front of you and vehicles with a large amount of ground clearance
or protruding freight, are often identified late or may not be
detected at all.
Fig. 151 The vehicle in
front is outside the
range of the radar
sensor
Fig. 152 A vehicle is
changing lanesFig. 153 Motorcycle in
front
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adaptive cruise control (ACC) 142Applies to vehicles: with adaptive cruise controlStationary vehiclesIf a vehicle detected by the ACC system turns off or changes lane
and another stationary vehicle is located in front of that vehicle, the
ACC system will not react to the stationary vehicle ⇒fig. 154 and
⇒fig. 155.
Audi braking guardApplies to vehicles: with adaptive cruise controlDescription
Audi braking guard warns you in case of an impending
collision with a vehicle in front.Audi braking guard is active at speeds above approximately 30 km/h
and operates within the system limitations ⇒page 140 even when
the adaptive cruise control is deactivated.
The radar sensor is fitted at the front of the vehicle ⇒page 130,
fig. 137. The system requires reflecting surfaces in order to be able
to measure the distance. If the ACC is unable to measure the
distance it will not respond.
Once the system has measured the distance, it can assess a
dangerous situation where a vehicle in front brakes suddenly or you
are driving fast and approach a vehicle travelling at a much slower
speed. The system warns you as soon as it anticipates that a poten-
tial collision with the vehicle in front can only be avoided by hard
braking or by taking evasive action.
The system has a preset response time so that it can warn you in
time. In certain situations, the system response time will be reduced
dynamically, e.g. when you are accelerating onto a motorway.
Braking, lateral acceleration and steering angle are other factors
Fig. 154 Vehicle
turning off and vehicle
stationaryFig. 155 Vehicle
changing lane and
vehicle stationary
Fig. 156 Instrument
cluster: Display
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