911 Carrera 4 Cabriolet (996) F6-3.6L (2003)
Alarm Module: Service and Repair
Removing and Installing Signal Converter/Immobilizer 
WM 967219 Removing and installing signal converter/immobilizer 
1. Disconnect the battery and cover terminal or battery.
2. Remove left side vent.
3. The signal converter on the ignition steering lock housing can be removed through the opening in the dashboard.
4. Open the locking button with a (short) cross-head screwdriver (1/4 turn counter-clockwise). Pull the signal converter out of the holder to the rear.
The figure shows the signal converter without dashboard.