airbag AUDI A4 1999 B5 / 1.G Airbag Service Workshop Manual

69-40


Airbags, servicing

Airbag system, safety precautions


WARNING!

Checking, removing, installing and servicing
may ONLY be performed by qualified
personnel.
Never perform tests using a test light or
multimeter.
Airbag system may only be tested when
installed in vehicle using VAG1551/VAG1552
scan tool.
Battery must be disconnected before
performing any work on airbag system.
Work can begin immediately after
disconnecting the battery.
When connecting the airbag system to a
voltage source, no one should be in the
vehicle interior.
Always install airbag units in the vehicle as
soon as they are removed from the
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packaging.
If installation work is interrupted,
immediately return the airbag unit to its
original packaging.
NEVER leave an airbag unit unattended.
After removing from the vehicle, ALWAYS lay
the airbag down with impact absorbing pad
(padded side) facing up.
Never attempt to open or service airbag
components. Always use new parts.
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69-41

WARNING!

DO NOT install an airbag unit that has fallen
on a hard surface or experienced mechanical
damage.
Airbag units have an expiration date (see
sticker on B-pillar). If airbag units are
replaced, pull sticker with expiration date off
new airbag unit and place it over old sticker
on B-pillar. Airbag unit and sticker must be
replaced after 14 years.
If there is no sticker on the B-pillar, airbag
change must be indicated in service plan.
Airbag unit must not be treated with grease,
cleaners or similar materials and must not be
exposed to temperatures above 100 C (212
F), even for short periods.
Always use the following work sequence when
replacing airbag units:

1 - Remove old airbag unit and lay down with
padded side facing up, for side curtain airbag,
observe additional safety precautions page
69
-49
.

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2 - Remove new airbag unit from transport
container and lay down with padded side facing
up, for side curtain airbag observe additional
safety precautions page 69
-49
.

3 - Immediately place old airbag in transport
container.

4 - Install new airbag in vehicle.
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69-42

Airbag units, replacing after an accident


Accident with activation of airbag and belt
tensioners (up to and including airbag 7)
Airbag control module must be replaced after
every activation of airbag and belt tensioners

Accident with activation of airbag and belt
tensioners (for airbag 8) (integrated as of
10/98)

Notes:

For vehicles with airbag 8, display will indicate
airbag front and side or airbag front and side
curtain.
Airbag control module can be used for up to
three side-/side curtain airbag and/or belt
tensioner activations.
After the third activation, the DTC "Control
Module Malfunctioning" will appear.
Airbag control module must be replaced:
After driver-side and/or passenger-side airbag
deployment.

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If housing is damaged.
If there is a deformation of body channel, within
a circumference of 200 mm around control
module.
After three side-/side curtain airbag
deployments.
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69-43

All models

Always replace any deployed airbag unit and
the following
Also replace the following if passenger-side
airbag deployed:

Flap and mounting frame for airbag (do not
reshape deformed mounting frames) and
instrument panel (if damaged).
Lateral acceleration sensor (if floor pan in area
near sensor is deformed).
Also replace the following if driver-side airbag
deployed:
Spiral spring with slip ring.
Lateral acceleration sensor (if floor pan in area
near sensor is deformed).
Also replace the following if side airbag
deployed:
Lateral acceleration sensor for the deployed
side airbag.

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69-44
Also replace the following if side curtain airbag
deployed:

Acceleration sensor for deployed side airbag.
Molded headliner.
Trim panels at A-pillar, B-pillar, C-pillar and D-
pillar.
Acceleration sensor that hasn't been activated
(if floor pan in area near sensor is deformed).
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69-45

Also
All seatbelts with activated belt tensioners.
On Board Diagnostic will recognize if belt
tensioners have been activated for airbag V, 7
and 8.

A - if airbag control module has been
triggered:
Front seat belt tensioners: Read Measuring Value Block 1
1
2
3
4

Repair Manual, Body On Board Diagnostic (OBD), Repair Group 01

Rear seat belt tensioners: - Read Measuring Value Block display group 1:
Activated belt tensioners can be identified by "0111" or "too large"
indicated on display.
Read Measuring Value Block 2
1
2
3
4

Repair Manual, Body On Board Diagnostic (OBD), Repair Group 01
- Read Measuring Value Block display group 2:
Activated belt tensioners can be identified by "0111" or "too large"
indicated on display.
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69-46

B - If airbag control module is replaced:

- Check DTC memory:

Repair Manual, Body On Board Diagnostic
(OBD), Repair Group 01


Activated belt tensioners can be identified by the
DTC: "Ignitor for belt tensioner - resistance is too
high"

- If necessary (visual check) also replace: all
damaged components.

Accident without airbag deployment
If airbag Malfunction Indicator Lamp (MIL) -K75-
does not indicate a DTC, then airbag
components do not need to be replaced. Check
seat belts separately.
After replacing airbag units or the control module,
attach label (only tear-off strip) to registration
card and send in registration card.
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