System components

ADAPTIVE CRUISE CONTROL A8 AUDI

Operation:
The speed control sender G259 transmits the
frequency-modulated signal and receives the
reflected signal. The control unit processes
the radar signals and other additional input
signals. These signals are used to determine
the relevant vehicle in front for control purposes
from all the objects in the radar detection
range.

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The position and speed of the vehicle, as well
as the current distance, are established. The
necessary control action is derived from this
data and the appropriate information transmitted
to the Motronic control unit J220,
automatic gearbox control unit J217 and ESP
control unit J104.
The data are transferred by way of the distance
control CAN and diagnosis interface for
data bus (gateway) J533 to the drive system
CAN.

Cover for distance control sender
The cover of the speed control sender in the
bumper trim panel is made of radar-permeable
material.
Any surface changes, such as subsequent painting or the attachment of stickers or other
items may lead to malfunctions.
The cover can be heated to prevent possible
malfunctioning due to snow a

System functions

Operation and driver information concept

Operating and display concept
Operation is by way of the adaptive cruise
control stalk on the left side of the steering
column.

The display concept includes three display
blocks:

All important information is always centrally
displayed in the speedometer.

Important information of relevance to the
system which does not have to be displayed
permanently on account of its infrequent
occurrence appears on the info line in the
centre display of the dash panel insert.

 

Additional information giving details of system
functions can be called up by the driver
in an extra display. This involves pressing the
RESET button on the underside of the wiper
stalk.

A distinction is made between 4 system statuses (modes):
ACC OFF
The system is deactivated and system operation is not possible.
ACC READY
This mode represents a standby status. The system remains switched on but no active control
takes place. If adaptive cruise control had previously been active, the desired speed is present
in the memory.
ACC ACTIVE
The adaptive cruise control implements the set speed (on an open road) or regulates the distance
from the vehicle in front.
ACC OVERRIDE
The driver exceeds the set speed by pressing the accelerator.