In order to provide the occupants with a good level of
protection, the vehicle should be able to detect hazards
early and use the latest technology to prepare the
vehicle. This is the idea behind Audi pre sense.

Audi pre sense Basic
Automatic belt tensioner function
If the front occupants have fastened safety belts and a
speed signal of approximately 9 mph is detected (driving
forwards), the Front Left and Right Safety Belt Tensioner
Control Modules J854 and J855 reduce the belt slack.
This is done by briefly activating the electric motors in
the belt retractors.

After the gentle tensioning, the safety belt tension is
released. If the front safety belts are fastened and the
vehicle is driving forwards at a speed of < 9 mph, the belt
slack is reduced after approximately 10 seconds. If the
safety belts are not fastened, the electric motors in the
belt retractors are not activated.

The occupants have the option of activating or
deactivating the automatic safety belt tensioner function
(belt slack reduction) using the MMI.

605_084

34

Audi pre sense
Longitudinal Dynamics Function
When this pressure raises quickly in a defined time, the
safety belts are fully tensioned electrically by control
modules J854 and J855.

If the vehicle is moving forward and the driver brakes
heavily, the Front Left and Right Safety Belt Tensioner
Control Modules J854 and J855 initiate the partial
tensioning of the safety belts when a certain brake
pressure is reached.

The ABS Control Module J104 also activates the hazard
warning flashers. Depending on the situation, the
forward motion of the occupants can be reduced to
approximately 4 in (100 mm) by tensioning of the safety
belts.

This is detected when a driver applies sudden and hard
brake pressure. The hydraulic pressure in the system
raises quickly.

Transverse Dynamics Function
If the vehicle oversteers or understeers, the Electronic
Stability Program (ESP) is activated.
The safety belts are partially tensioned electrically.
If the vehicle exceeds its physical limits and can no
longer be stabilized, the safety belts are fully tensioned
electrically.

Without RBT2)

In addition, the side windows and the tilt/slide sunroof1)
are closed (if open).
If no accident occurs in any of the driving situations
described here, the safety belts are released and the
hazard warning flashers deactivated (if activated).

With RBT2)

Depending on the set-up in Audi drive select and if ESC
is active or deactivated, the safety belts are tensioned
electrically for the driving situation.
605_085

Audi Drive Select

ESC

Auto

Comfort

Dynamic

On

Partial and Full

Partial and Full

Full

Off

Partial and Full
Under Braking

Partial and Full
Under Braking

Full Under Braking

Because of the speed at which events occur, the side
windows and the tilt/slide sunroof1) cannot always be
fully closed.

1)
2)

Closing the side windows and the tilt/slide sunroof
reduces the possibility of miscellaneous objects
entering the occupant cell.

Optional Equipment
Reversible Safety Belt Tensioner

35

Audi pre sense
Audi pre sense Plus
Audi pre sense Plus requires the optional Adaptive Cruise
Control (ACC) system. The ACC system also includes
the Audi braking guard. The ACC radar sensors monitor
the traffic ahead (within the scope of their technical
capabilities) and send the information to the Distance
Regulation Control Module J428. The data is evaluated
and relevant information is sent out over the data bus.
Other control modules are able to receive and evaluate

these messages and take appropriate action. Even when
ACC is inactive for the driver, the radar sensors monitor
the traffic ahead and send the data across the data bus.
Both the optional ACC and Audi side assist are required
to implement the Audi pre sense plus system. Audi side
assist monitors the traffic behind the vehicle.

Example of a Situation:
Phase 1: When the vehicle approaches a hazardous
situation, the driver is alerted audibly and visually by
the Instrument Cluster Control Module J285. At the
same time, the ABS Control Module J104 prefills the
brake system, and the Level Control System Control
Module J197 sets the damping to "firm."

Phase 3: This phase applies to Audi pre sense

plus only. If the driver still does not apply the brake,
approximately 50% braking force is applied by the ESP
control module. In addition to this:

• The emergency braking function (hazard warning
flashers) is activated by J428

Phase 2: If the driver does not respond to the

warnings indicated in the instrument cluster or only
eases off the accelerator, the ESP control module
performs a warning braking of about 30%. The belt
slack in the safety belts is reduced during the warning
braking phase by the Left and Right Safety Belt

• Side windows and the sunroof are commanded to

Tensioner Control Modules J854 and J855.

only). An emergency braking operation of approximately
100 % braking force is initiated, reducing the severity
of the collision. In addition, the safety belts are fully
tensioned electrically.

1)

36

close by the safety belt tensioner control module on
the driver's side

Phase 4: This phase applies to Audi pre sense plus

Phase 1

Phase 2

Phase 3

Phase 4

− Audible and Visual Warnings

− Warning Braking

− Prefilling of the Brake System

− Belt Slack Reduction

− Partial Braking Operation 2
(approx. 50 %)

− Reversible Safety Belt Tensioners
− Emergency Braking

− Damper Adjustment

− Partial Braking Operation 1
(approx. 30 %)

Optional Equipment

− Closing of Tilt/slide Sunroof
− Emergency Flashing

605_086

Audi pre sense
Additional Examples:
If the driver accelerates sharply in Phases 2 and 3
despite all of the warnings, the partial braking operation
is cancelled after the warning braking. The ACC system
determines that the driver knows of the dangers and is
in control of the vehicle. No further braking operation is
initiated by the ACC system.
If the driver brakes in phase 1, Audi braking guard
determines that the driver has been alerted and takes no
further action.

If the driver enters a danger zone during normal
operation and underestimates the situation, Audi pre
sense Plus assists the driver. If the driver does not
brake hard enough, the Audi braking guard may assist by
increasing the brake pressure.
If the driver does not want the Audi braking guard
function, it can be deactivated through the MMI. It is
possible to deactivate only audible, only visual or the
entire Audi braking guard system including the following
functions: warning braking, partial braking, emergency
braking and emergency flashing.

605_087

Audi pre sense Plus
The information which the Distance Regulation Control
Module J428 sends through the data bus to all control
modules. The Airbag Control Module collects key
information such as "time to collision" and "speed
relative to objects ahead." When a set value is exceeded,

Airbag Control Module is aware that a collision is
imminent. The electronics in the Airbag Control Module
are alerted and wait for information from the crash
sensors.

37

Audi pre sense
Audi pre sense Plus
Audi pre sense Plus uses Audi side assist and supplies
information on traffic behind the vehicle. The system
uses radar sensors in the bumpers to continuously feed
the Lane Change Assistance Control Module J769 with
information.

The Audi lane assist control module evaluates this
information and adds any relevant information to the
data bus. Even if Audi side assist is deactivated by the
driver, J769 still continues to send relevant data.

Example of a Situation:
Phase 1:

Phase 2:

If a vehicle is approaching quickly from behind, the
driver’s front safety belt tensioner control module sends
this information to the data bus. The side windows
and the tilt/slide sunroof) begin closing and the hazard
warning flashers are activated. If the vehicle has memory
seats in the front, the head restraints move into their
upper position. If the vehicle has comfort seats in the
front and memory seats in the rear, the head restraints
on all seats are moved into their upper position and the
upper seat backs are tilted forwards.

If the vehicle continues to approach and a collision is
determined to be unaviodable, the front safety belts are
tensioned electrically.

Adjustment of the head restraints and upper seat backs
is model dependent.

Phase 1
− Activate Hazard Warning Flashers
− Seat Position
− Close Sunroof/Windows

Phase 2
− Reversible Safety Belt Tensioners

605_088

On models with a trailer hitch, Audi pre sense rear is not active if a trailer is detected.

1)

Optional Equipment

38

Audi pre sense
Data Bus Networking
The overview shows some of the information which is exchanged via data bus.
> = data is transmitted

< = data is received

without > / < = initiated actions

ABS Control Module J104

Distance Regulation Control Module J428

Prefill Brake System <
Warning Braking <
Partial Braking Operations 1 and 2 <
Emergency Braking <

Distance the Objects in Front >
Speed Relative to Objects in Front>
Time to Collision in Front >
Prefill Brake System >
Warning Braking >
Partial Braking Operations 1 and 2 >
Emergency Braking >
Damper Adjustment >
Audible and Visual Warnings >
Activate Hazard Warning Flashers >

Vehicle Speed >
Forward/Reverse >
Brake Pressure >
ASR Status >
Activate Hazard Warning Flashers >

Lane Change Assistance Control Module J769
Level Control System Control Module J197
Damper Adjustment <

Instrument Cluster Control Module J285
Audible and Visual Warnings<
Vehicle Speed<

Distance to Objects in Rear >
Seed Relative to Objects in Rear >
Time to Collision in Rear >
Sensor Electronics Control Module J849
Longitudinal Acceleration >
Transverse Acceleration >
Rotation about Vertical Axis >
Inclination >
Steering Column Electronics Control Module
J527

Left Front Safety Belt Tensioner Control Module
J854
Status of Safety Belt Buckles<
Distance to Objects Front and Rear<
Speed Relative to Objects Front and Rear<
Time to Collision Front and Rear>
Vehicle Speed<
Activate Hazard Warning Flashers>
Close Side Windows>
Close Tilt/Slide Sunroof>
Extend Head Restraint>
Adjust Upper Seat Back Forwards>
Belt Slack Reduction
Electrical Partial Tensioning
Electrical Full Tensioning

Right Front Safety Belt Tensioner Control
Module J855
Status of Safety Belt Buckles<
Distance to Objects Front and Rear<
Speed Relative to Objects Front and Rear<
Time to Collision Front and Rear>
Vehicle Speed<
Belt Slack Reduction
Electrical Partial Tensioning
Electrical Full Tensioning

Cruise Control System Status >

Active Steering Control Module J792
Steering Lock>

Airbag Control Module J234
Status of safety belt buckles>

Comfort System Central Control Module J393
Activate hazard warning flashers<

Power Sunroof Control Module J245
Close Sliding Sunroof<

Door Control Modules J386, J387, J388, J389
Close Side Windows<

Engine Control Module J623
Accelerator Pedal Position>

Seat Adjustment Control Modules J136, J521,
J876, J877
Extend Head Restraint<
Adjust Upper Seat Back Forwards<

Information Electronics Control Module 1 J794
Audi Drive Select Set-Up>

605_089
39

Airbag and Pyrotechnic System Precautions
Precautions
There are certain precautions that you should always take when working on an airbag system.

• Refer to the repair manual for the latest warnings and cautions as well as other important information on
airbags and pyrotechnic devices.

• Empty pockets of pencils, pens, cigerettes, and other items that could fall out.
• Disconnect the battery ground (GND) strap before working on the airbag or pyrotechnic safety belts.
• Wear O.S.H.A approved safety goggles with a minimum ANSI rating of ANSI Z87_1_1968 and ANSI Z87_1_1989.
Flying material released during an inadverent deployment can damage eyesight or cause blindness.

• Electrostatically discharge yourself before handling an airbag or pyrotechnic safety belt. Do this by touching a
suitable metal part, such as a door jam striker pin or ground point.

40

Airbag and Pyrotechnic Systems Precautions
When Working on Vehicles
There are quite a few things a Technician needs to know when working on vehicles with Airbags
and pyrotechnic safety belts.

• NEVER erase Diagnostic Trouble Codes (DTCs) before discovering the root cause of an airbag fault.
• Never open or attempt to repair an airbag module or pyrotechnic safety belts.
• Do not install airbag components or pyrotechnic safety belts that have been dropped or show signs of damage.
• Never use a (nine volt) battery saver. Using a battery saver can cause an airbag or safety belt pretensioner to deploy.
• Never use a digital volt ohmeter or self powered test light when working on an airbag or pyrotechnic safety

belt system. Using the wrong diagnostic tools can cause and airbag or safety belt pretensioner to deploy. Use
only approved Audi diagnostic tools on airbag and pyrotechnic safety belt systems.

• Never use impact tools to remove or install pyrotechnic safety belts.
• Do not hammer in the area of pyrotechnic safety belts, the airbag control module or crash sensors. See ElsaWeb
for the location of sensors that trigger safety belts and airbags.

• Do not use grease, cleaning solutions, solvents or similar substances on safety belts or airbag covers.
• Do not appy stickers or badges to airbag covers.
• Do not use salvage parts when repairing a safety belt or airbag system.
• Never turn the ignition to the ON position while reaching through the steering wheel spokes. The airbag could deploy
and cause serious injury.

• Do not disable any safety systems on the vehicle
• Always wash your hands and face with mild soap and water after working on a vehicle in which the airbags and other

pyrotechnic deveices have been deployed, especially before eating. Also, do not let the particles and dust released
from an airbag or pyrotechnic safety belt get into your eyes or into any cuts or scratches. If contact does occur, flush
eyes with water and wash exposed skin with soap and water.

41

Special Handling
On the following pages you will learn some of the special handling rules to follow for
airbags and pyrotechnic safety belts.

• All airbags and pyrotechnic safety belts of a vehicle scheduled to be scrapped must be deployed using Airbag
Deployment Device J-44210. Always read the instruction booklet and view the supplemental video for Airbag
Deployment Device J-44210 and heed all warnings before using the device.

• Undeployed airbags and pyrotechnic safety belts are considered hazardous material. When disposing of an

undeployed airbag or pyrotechnic safety belt that is either defective or expired, use the appropriate repair information
and Airbag Deployment Device J-44210. Never deploy airbags or pyrotechnic safety belts in the vehicle.

• If airbag or pyrotechnic safety belt cannot be safely deployed or removed from the vehicle, contact the Audi Dealer
Technician’s Helpline.

• Make sure your dealer complies with federal, state and local regulations for explosive substances.
• Deployed airbags and pyrotechnic safety belts can be disposed of as normal scrap.
• Shipment of active, undeployed airbag gas generators and pyrotechnic safety belt retractors must be in accordance

with the regulations published in the latest edition of the Code of Federal Regulations #49 (49 CFR). Shipment must
be initiated and received by certified individuals. The penalties for noncompliance are severe. Civil penalties range
from $250 to $27,500 per violation, per day. Criminal penalties, for willfully violating the regulations, range from
$250,000 for individuals and $500,000 for corporations.

42

Special Handling
Special Procedures

!
!
!

NEVER erase Diagnostic Trouble Codes (DTCs) before discovering the root cause of an airbag fault.

Refer to the latest repair information in ElsaWeb to determine which components have to be
replaced in the event of airbag and pyrotechnic safety belt deployment.

Inspect pyrotechnic safety belts even if the airbag(s) did not deploy.

43

Special Tools
Airbag Deployment Device J-44210
State and federal law requires airbags and safety belt
tensioners to be deployed before being discarding.
The J-44210 Deployment Fixtures assists certified
technicians on the deployment of Audi driver, passenger,
side-impact airbags and safety belt tensioners for the
purpose of disposal.
The fixture functions as a platform to which airbags
and tensioners can be attached for deployment. It

44

incorporates a plastic tank that must be filled with water
prior to use. It also includes the necessary bolts and
brackets to properly attach the airbag/tensioners.
It is important that the technicians is familiar with
all procedures to attach and deploy airbags using
this device. Additional information regarding these
procedures can be found on Servicenet in the J44210
Instruction Booklet.

Special Tools
VAS 5056
The VAS 5056 simulates the resistance of the airbag.
It can also simulate a short circuit when the button on
the tester is pushed. The tester comes with adapter
harnesses to fit all airbag and pyrotechnic safety belt
igniter connectors.
For example, for the DTC Front Passenger Airbag Igniter
1-N131-Too High, a technician can connect the VAS 5056
and the proper adapter to the igniter wiring harness and
monitor the Measuring Value Blocks on the Scan Tool.
When the technician pushes the button on the tester,
the value should change from Too High to Too Low. If
this happens, the technician has verified that the wiring
harness to the airbag is not the cause of the DTC. Always
refer to the electronic service information systems and
Guided Fault Finding for the latest diagnostic and repair
information.

45

Notes

46

Knowledge Assessment
An online Knowledge Assessment (exam) is available for this Self-Study Workbook.
The Knowledge Assessment is required for Certification.
You can find this Knowledge Assessment at:

www.accessaudi.com
From the accessaudi.com Homepage:

• Click on the “ACADEMY” tab

• Click on the “Academy Site” link
• Click on Course Catalog Search and select “970133B — Audi Occupant Protection –

Passive Systems II, Audi pre sense”

Please submit any questions or inquiries via the Academy CRC Online Support Form
which is located under the “Support” tab or the “Contact Us” tab of the Academy CRC

Thank you for reading this Self-Study Workbook and taking the assessment.

47

970133
All rights reserved.
Technical specifications subject
to change without notice.
Audi of America, LLC
2200 Ferdinand Porsche Drive
Herndon, VA 20171