Audi Q7 2017 Manual page 13

Activation of the electrically reversible safety belt tensioners
When corrective adjustments are made by Audi pre-sense,
Airbag Control Module J234 initiates tensioning of the
safety belts via Left and Right Front Seat Belt Tensioner
Control Modules J854 and J855. They communicate with
each other through a sub-bus system.
Terminal 30
Airbag Control Module J234 is connected to Terminal 30
and Terminal 15. In addition, it receives digital information
on the status of Terminal 15 from Data Bus On Board Diag-
nostic Interface J533 through a discreet wire. The airbags
will only deploy when the ignition is switched on.
A capacitor is integrated with Airbag Control Module J234.
Its function is to provide power if Terminal 30 or 15 is
disconnected during a vehicle crash.
Key:
A Battery
J234 Airbag Control Module
J367 Battery Monitoring Control Module
J519 Vehicle Electrical System Control Module
J533 Data Bus On Board Diagnostic Interface
Diagnostics
The Airbag Control Module is diagnosed with the VAS Scan
Tool using Address Word 15.
Because there are tolerances when installing the Airbag
Control Module, the internal inertial sensors must be
calibrated so they will accurately measure the X , Y axes
and the yaw rate about the Z axis.
From the topology chart
Data Bus On Board
Diagnostic Interface
J533
FlexRay
Airbag Control Module
J234
LIN bus
Passenger Occupant
Detection System Control
Module
J706
Function diagram
LIN bus
If a new control module is installed but not calibrated,
the DTC - "C115E54 inertial sensors no basic setting" is
recorded in its fault memory.
The inertial sensors must be calibrated after the following
work:
• Removal/installation of Airbag Control Module J234.
• Replacement of Airbag Control Module J234.
Left Front Seat Belt
Sub-bus
Tensioner Control Module
J854
Right Front Seat Belt
Tensioner Control Module
J855
FlexRay
637_008
637_018
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