BMW 3 (E46). Manual — part 303

immediately.

Airbag(s) are inflated by an
explosive device. Handled
improperly or without adequate
safeguards, the system can be
very dangerous. Special
precautions must be observed
prior to any work at or near the
airbags.

The airbag is a vehicle safety
system. Serious injury may result
if system service is attempted by
persons unfamiliar with the BMW
MRS II and its approved service
procedures. BMW advises that all
inspection and service be
performed by an authorized BMW
dealer.

Always disconnect the battery and
cover the negative (-) battery
terminal with an insulator before
starting diagnostic,
troubleshooting or service work
not associated with the airbags,
and before doing any welding on
the car.

After disconnecting the battery,
wait 5 seconds before beginning
work on airbag components.

If an airbag has been activated
due to an accident, BMW specifies
that airbag components be
replaced. For more information on
post-collision airbag service, see
an authorized BMW dealer.

Do not fire an airbag unit prior to
disposal. It must be fired by a

special disposal company or
shipped back to BMW in the
packaging of the new
components.

When removing a fired airbag unit,
avoid contact with the skin; wear
gloves. In case of skin contact,
wash with water.

Do not allow airbag system
components to come in contact
with cleaning solutions or grease.
Never subject airbag components
to temperatures above 167F (75C).
When reconnecting the battery, no
person should be inside the
vehicle.

Always place an airbag unit that
has been removed from its
packaging with the padded side
facing upward. Do not leave an
airbag unit unattended.

If the airbag unit or airbag control
module has been dropped from a
height of meter (1 ft.) or more, the
airbag unit should not be
installed.

721-2

Airbag Electronics

Airbag harnesses and
connectors

If airbag connection harnesses show
visible signs of wear or damage, they
must be replaced or repaired.

-

To repair airbag harness:

Disconnect negative (-) cable from
battery and cover negative
terminal with insulating material.

Disconnect harness connector at
airbag module or on intermediate
plug.

Cut through one cable, then the
other, and repair.

CAUTION!

Do not under any circumstances
cut through both wires of an
airbag harness at the same time.

Perform only one repair on an
airbag harness wire. If more
than one spot is damaged,
replace the entire section of
harness.

MRS control module, replacing

-

Disconnect negative (-) cable from
battery and cover negative
terminal with insulating material.

CAUTION!

Prior to disconnecting the battery,
read the battery disconnection
cautions given at the front of this
manual on page viii.

-

Remove center utility tray between
front seats. See

513 Interior

Trim

.

Cut open carpet on top of center tunnel
to access MRS II module.

-

Remove module mounting nuts
and lift up control module. Detach
electrical harness connector.

-

Installation is reverse of removal.

Be sure that MRS module ground
cable is attached to the module
mounting stud.

Side-impact crash sensor,
removing and installing

-

Make sure ignition key is OFF.

-

Remove front seat. See

520

Seats

.

Remove plastic door sill trim by lifting
to release clips at one end, then sliding
off. Fold up carpet towards rear seat
floor. If necessary, remove floor level
heater duct.