Audi Q7 User Manual

8
X
Y
Centre crash sensor for X/Y axis G858
The centre crash sensor for X/Y axis G858 is an acceleration sensor.
A combination sensor, the centre crash sensor for X/Y axis, meas-
ures both vehicle acceleration and deceleration in the Y and Y
directions.
The centre crash sensor for X/Y axis is used to validate the plausi-
bility of defined crash situations in the longitudinal (X) and trans-
verse directions (Y).
Installation location
In the AudiQ7, the centre crash sensor for X/Y axis G858 is located
on the centre tunnel rear in proximity to the rear cross member for
the driver's seat.
637_011
637_010
Airbag control unit J234
Sensors and data bus interface
The airbag control unit J234 in the Audi Q7 has undergonme
extensive modification.
The sensors which measure acceleration in the X and Y directions
and yaw rate about the vehicle's Z axis (inertial sensors) are now
positioned directly on the airbag control unit J234. To enable the
ESC signals to be transmitted on the data bus with guaranteed
minimum reaction time of about 2 ms, the control unit was
rerouted from the powertrain CAN bus to the FlexRay bus.
In functional terms, therefore, the airbag control unit J234 records
body movement and provides this data via the FlexRay bus to ABS
control unit J104, among others. The ABS control unit J104 is also
connected to the FlexRay bus. The ABS control unit processes the
data it receives from the airbag control unit and takes the appro-
priate action, e.g. stabilision of vehicle by corrective braking
(ESCcontrol).
Centre crash sensor
for X/Y axis
G858
Airbag control unit
J234
Coordinates
637_050
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Audi Q7 Specifications

General

Brand	Audi
Model	Q7
Category	Automobile
Language	English