Self-Study Program 970133

Audi Occupant Protection Systems

Audi of America, LLC
Service Training
Produced 4/2013
Course Number 970133
©2013 Audi of America, LLC
All rights reserved. Information contained in this manual
is based on the latest information available at the time of
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information should be referred to Audi of America, LLC.
Always check Technical Bulletins and the latest electronic
repair literature for information that may supersede any
information included in this booklet.

rev. 2 5/2013

Table of Contents
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Passive Versus Active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Passive Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Front Airbags. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Adaptive Driver’s Airbag. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Side Airbags. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16

Side Curtain Airbags. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18

Adaptive Belt Force Limitation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20

Roll-Over Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24

Seat Position Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

26

Market-Specific Special Features . . . . . . . . . . . . . . . . . . . . . . . . . . .

28

Occupation Protection Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

28

Passenger Front Airbag. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

29

Passenger Occupant Detection System. . . . . . . . . . . . . . . . . . . . . . .

30

Passenger Side Seat Occupant Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30

Installation Position. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31

System Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

32

Gel Mat System Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

33

Audi pre sense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

34

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

34

Audi Pre Sense Basic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

34

Longitudinal Dynamic Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35

Transverse Dynamics Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35

Pre Sense Plus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36

Data Bus Networking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39

Airbag and Pyrotechnic System Precautions . . . . . . . . . . . . . . . . .

40

Special Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

42

Special Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Special Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VAS 5056. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Knowledge Assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

43

44
45

47
i

The Self-Study Workbook provides introductory information regarding the design and
function of new models, automotive components or technologies.
The Self-Study Workbook is not a Repair Manual!
All values given are intended as a guideline only.
Refer to the software version valid at the time of publication.
For maintenance and repair work, always refer to the current technical literature.
ii

Reference

Note

!

Introduction
Audi has a long history of pursuing vehicle safety. The
first crash tests were conducted in 1938. While those
early tests were done in pursuit of the same goal of
occupant protection, technology has increased the scope
to levels never dreamed of at that time.
Today, the development of a new vehicle requires more
than just crash testing. It involves a systemic approach
that includes many vehicle components and how they
work together not only for crash survival but also in
crash avoidance. Naturally, computers play a large role
but actual vehicle testing is always carried out.

The engineers of Audi AG not only evaluate the results of
in-house tests, but also actual accidents recorded by the
accident researchers and scientists at the Audi Accident
Research Unit (AARU). The AARU works hand-in-hand
with police and doctors to compile as much accident data
as possible. Using this information, Audi is constantly
working to refine its test parameters.
The focus of Audi vehicle safety is on people. When it
comes to safety, Audi relies on its most special people its crash test dummies.

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1

Introduction
This Self-Study Program cannot cover the specific details
for all Audi models. Specific information for each model
is included with that model’s introductory information.
Highly sophisticated passenger protection features
such as those described in this Self-Study Program help
prevent serious injury to our customers in the event of a
crash. However, the best precaution to prevent or reduce
serious injury during a crash is from wearing a properly
fastened safety belt.

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2

Introduction
Passive Versus Active
Passive safety systems are designed to reduce injuries during or after a crash event.
Active systems are designed to help the driver avoid a crash event.
The passive safety system components are:

The active safety system components are:

• Airbag control module
• Driver and passenger airbags
• Side airbag
• Curtain airbags
• Crash sensors
• Safety belt tensioners and belt force limiters
• Safety belt reminder indicator
• Driver and passenger seat position sensors
• Battery isolator elements (only for vehicles with the

• Braking systems such as ABS, ESC, TCS, EBD
• Tire pressure monitoring
• Adaptive cruise control
• Adaptive headlamps
• Audi pre sense
• Parking Aids
• Reverse camera
• Audi side assist
• Night vision

•
•
•
•

battery in the interior or luggage compartment)
Safety belt buckle switches
Passenger seat occupant sensor
Key switch for deactivating the passenger front
airbags with accompanying warning lamp
Roll-over protection (convertible models)

3

Passive Systems
System Overview
The system overview shows the equipment options available for an Audi A7. Not all of these components are available or
installed on every model.
Key:
E24
E25
G179
G180
G256
G257
G283
G284
G452
G551
G552
G553
G554
J234
J285
J393
J533
J623
J706
J854
J855

4

Driver Safety Belt Switch
Front Passenger Safety Belt Switch
Driver Side Airbag Crash Sensor
Front Passenger Side Airbag Crash Sensor
Driver Side Rear Side Airbag Crash Sensor
Passenger Side Rear Side Airbag Crash Sensor
Driver Front Airbag Crash Sensor
Passenger Side Front Airbag Crash Sensor
Passenger Occupant Detection System Pressure
Sensor
Driver Belt Force Limiter
Front Passenger Belt Force Limiter
Driver Seat Position Sensor
Front Passenger Seat Position Sensor
Airbag Control Module
Instrument Cluster Control Module
Comfort System Central Control Module
Data Bus On Board Diagnostic Interface
Engine Control Module
Passenger Occupant Detection System Control
Module
Left Front Safety Belt Tensioner Control Module
Right Front Safety Belt Tensioner Control Module

K19 Safety Belt Indicator Lamp
K75 Airbag Indicator Lamp
K145 Front Passenger Airbag -Disabled- Indicator Lamp
(optional)
N95 Driver Airbag Igniter
N131 Front Passenger Airbag Igniter 1
N132 Front Passenger Airbag Igniter 2
N153 Driver Safety Belt Tensioner Igniter 1
N154 Front Passenger Safety Belt Tensioner Igniter 1
N196 Driver Side Rear Safety Belt Tensioner Igniter
N197 Passenger Side Rear Safety Belt Tensioner Igniter
N199 Driver Thorax Airbag Igniter
N200 Front Passenger Thorax Airbag Igniter
N201 Driver Side Rear Thorax Airbag Igniter
N202 Passenger Side Rear Thorax Airbag Igniter
N251 Driver Head Curtain Airbag Igniter
N252 Front Passenger Head Curtain Airbag Igniter
N253 Battery Interrupt Igniter
N295 Driver Knee Airbag Igniter
N296 Front Passenger Front Knee Airbag Igniter
N490 Driver Airbag Release Valve Igniter
T16 16 Pin Connector, Data Link Connector

Passive Systems

A7_Airbag_USA

Powertrain CAN bus
Display and Operation CAN bus
Extended CAN bus
Convenience CAN bus
Diagnostics CAN bus
Input Signal
Output Signal
5

Passive Systems
Terminology Used for Airbags by Audi
The deployment stages of an airbag were previously
defined by the propellant charges, which inflate the
airbag with gas. Today, the deployment stages of an
airbag are determined by the number of igniters.

It does not matter if an igniter activates a propellant
charge or activates an adaptive feature (opens an
additional outlet orifice).

Igniter

Propellant Charges

Adaptivity

Old Designation
Settings

New Designation
Settings

1

1

None

1

1

2

2

None

2

2

2

1

Yes

1

2

3

2

Yes

2

3

Driver Airbag Igniter N95 for
Propellant Charge

Driver Airbag Release Valve Igniter
N490 for Adaptivity Function

Together, the igniter for the propellant charge and
igniter for the adaptivity function form a two-stage
airbag module.

6

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Passive Systems
Front Airbags

Driver Airbag Gas Generator

Two different style front airbag modules are used on
Audi models.

To deploy an airbag, the airbag control module sends an
electrical signal which ignites the priming charge. The
priming charge ignites the actual airbag propellant.

On the driver’s side there is a solid propellant generator,
and on the passenger side a hybrid gas generator which
inflates the airbag.
Depending on model, the gas generators of the front
driver’s side airbag modules are mounted in a rubber
ring to reduce the vibration transmitted to the steering
wheel.

When the gas pressure from the propellant charge is
high enough, the rupture foil opens the outlet orifices
and allows the gas to flow into the airbag. The airbag
unfolds and is inflated.

Priming Charge
Spacer

Outlet Orifice

Propellant Charge
Rupture Foil

Filter
Propellant Charge

Igniter

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7

Passive Systems
Adaptive Driver’s Airbag Gas Generator - Version 1
Depending on model, adaptive airbag modules can also
be used.

The actual propellant charge is ignited through holes in
the nozzles. When the gas pressure of the propellant
charge is high enough, the gas generator housing
deforms and allows the gas to flow into the airbag via
the inner housing and metal filter. The airbag unfolds
and is inflated.

The Airbag Control Module J234 activates igniter 1,
which in turn ignites the priming charge.

Cap
Propellant Charge

Housing

Priming Charge

Propellant Charge

Inner housing

Inner Housing

Metal Filter

Metal filter

Nozzle Orifice
Cord
Igniter 2

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Igniter 1
Nozzle Orifice

An additional igniter - the Driver Airbag Igniter 2 N250 is mounted on the back outside the gas generator.

A cord, which closes an additional outlet orifice by a
band, wrapped around this igniter.

Cord

Igniter 2
Igniter 1

8

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Passive Systems
Additional Outlet Orifice Closed
An additional outlet orifice in the airbag is sealed shut as
long as the cord from the igniter is held in position.

Cord

Outlet Orifice

Band

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Additional Outlet Orifice Open
Depending on impact severity and the driver’s seating
position, Airbag Control Module J234 activates Driver
Airbag Igniter 2 N250. The igniter housing ruptures and
the cord is released.
The volume of the airbag increases by about 4 liters, and
the additional outlet orifice is opened. As a result, more
gas can escape through this outlet orifice. In this way
the airbag is “adapted” to the severity of the crash and
the occupants’ seated position.

Outlet Orifice

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9

Passive Systems
Adaptive Driver’s Airbag Gas Generator — Version 2
The priming charge is ignited by igniter 1, which is
activated by Airbag Control Module J234.
The combustion of the priming charge causes the
pressure inside the capsule to increase until the capsule
ruptures and the propellant charge is ignited through
holes in the nozzles.

Metal Filter

When the gas pressure is high enough, the tab opens
the outlet orifices. The gas is now able to flow freely
through the metal filter into the airbag. The airbag
unfolds and is inflated.

Nozzle Orifices

Metal Filter

Foil

Foil

Outlet
Orifice

Outlet
Orifice

Propellant
Charge

Propellant
Charge
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Priming Charge

Capsule
Igniter 1
Distributor Housing

Driver Airbag Igniter 2 N250 is located inside the airbag
module.
The igniter is integrated with the base plate, a control
ring with orifices and the distributor housing.
Igniter 2
Control Ring

Retaining Clip