Audi A3 Sportback, Service, Page: 20 / 60

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The battery isolation igniter has the same task as
the battery cut-off relay.
This involves disconnecting the starter and
alternator leads from the vehicle battery in the event
of a crash. The battery isolation igniter is used only
on models whose battery is installed in the luggage
compartment.
The battery isolation igniter is activated and
monitored for diagnosis by the airbag control unit.
Every time the airbag is deployed, the battery
isolation igniter is activated and must be
subsequently replaced.
When the pyrotechnic propellant charge is ignited,
the developing gas pressure displaces the bolt
located on a piston and breaks the connection
between the two battery terminals.
Occupant protection
Battery isolation igniter, N253
332_014
332_030
Battery isolation igniter Battery isolation igniter activated
Connecting
element with
terminals
Pin
Detonator
332_031
Connecting
element with
terminals
Pin and piston
combination
Detonator