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Airbag (driver side) > < Exploded view of battery isolation igniter

A4 Mk3

Removing and installing battery isolation igniterN253
Removing and installing battery isolation igniter -N253-
Special tools and workshop equipment required
t  Vehicle diagnostic tester
Removing
  WARNING
t  Observe safety regulations for pyrotechnic components → Chapter.
t  Observe disposal regulations for pyrotechnic components → Chapter.
  Note
t  If airbag warning lamp -K75- is illuminated after an accident, use → Vehicle diagnostic tester to check whether crash data have been stored. If this is the case, check whether the fault »Resistance too high« is stored in the event memory for the battery isolation igniter -N253-. If this fault is stored in the memory, the battery isolation igniter -N253- must be renewed.
t  Each time the airbag is triggered, the battery isolation igniter -N253- electrically isolates the circuit. Battery isolation igniter -N253- must always be renewed after triggering.
t  The battery isolation igniter -N253- is only available as a replacement part together with the fuse holder A -SA-.
t  If you want to renew the battery isolation igniter -N253- separately, it can be detached from the replacement part and installed on the fitted fuse holder A -SA-, as described in the following.
–  Switch on ignition.
–  With ignition switched on, disconnect battery earth wire → Electrical system; Rep. gr.27.
   
–  Take out mounting for vehicle tool kit.
–  Remove nuts -2- and -3-.
  A69-10275
–  Release retaining spring -3-.
–  Slightly lift up flap -2- above fuse holder A -SA--arrow- and at the same time take out battery isolation igniter.
  Note
-Item 1- can be disregarded.
  A97-10316
  WARNING
Before handling pyrotechnic components (e.g. unplugging the electrical connector) the mechanic must discharge static electricity by briefly touching the door striker plate, or similar.
–  Detach battery isolation igniter -4-.
–  Release catch -5--arrow- and unplug electrical connector -1-.
Installing
  WARNING
t  Observe safety regulations for pyrotechnic components → Chapter.
t  Before handling pyrotechnic components (e.g. plugging in the electrical connector) the mechanic must discharge static electricity by briefly touching the door striker plate, or similar.
Installation is carried out in the reverse order; note the following:
  Note
Make sure electrical connectors are fitted correctly (as far as stop) and engage audibly.
  WARNING
The battery must be connected with the ignition switched on. If pyrotechnic components (e.g. airbag or belt tensioner) are inexpertly repaired, this may result in unwanted triggering after connecting the battery. There must not be anyone in the vehicle while you are connecting the battery.
–  With ignition switched on, connect battery earth wire → Electrical system; Rep. gr.27.
–  As a final step, interrogate event memory of airbag control unit -J234- and eliminate any faults → Vehicle diagnostic tester.
Tightening torque → Chapter
  A69-10275

Airbag (driver side) > < Exploded view of battery isolation igniter