Removing and installing battery isolation igniter N253 — AUDI

Removing and installing
battery isolation igniter
N253
Special tools and workshop equipment required
Vehicle diagnostic tester
Removing
WARNING
Observe safety regulations for pyrotechnic components
Chapter
.
Observe disposal regulations for pyrotechnic components
Chapter
.
Note
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.
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.
The
battery isolation igniter
N253
is only available as a replacement part together with the
fuse holder A
SA
.
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.
With ignition switched on, disconnect battery earth wire
Electrical system
Rep. gr.
27
.
Remove right A-pillar trim (bottom)
Chapter
.
Fold back footwell floor covering in area of A-pillar (passenger side).
Turn fasteners
1
and
3
by 90° (anti-clockwise) and open cover
2
.
Unscrew nuts
2
and
4
.
Detach the positive wire
5
.
WARNING
Before handling pyrotechnic components (e.g. unplugging the electrical connector) the mechanic must discharge any static electricity. This can be done by briefly touching the door striker plate, or similar.
Take out the battery isolation igniter
1
.
Unplug electrical connector
3
.
To do so, use a small screwdriver
1
to release connector locking element
3
and detach electrical connector
2
from
battery isolation igniter
N253
.
Installing
Install in reverse order of removal; note the following:
WARNING
Observe safety regulations for pyrotechnic components
Chapter
.
Before handling pyrotechnic components (e.g. plugging in the electrical connector) the mechanic must discharge any static electricity. This can be done by briefly touching the door striker plate, or similar.
Make sure electrical connectors are fitted correctly (as far as stop) and engage audibly.
Switch on ignition.
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
.
Finally read out event memory for airbag control unit using
Vehicle diagnostic tester
and rectify faults as necessary.
Tightening torque
Chapter
“
Exploded view of
battery isolation igniter
N253
”