Central locking — general information and replacement of components (Audi A4 B5)

1. Most models are equipped with a central locking system that automatically locks the doors and boot lid when any front door is closed with the key. The system is powered by an air pump, which creates a vacuum in the system when closing and an excess pressure when opening. Apart from the components of the system, the operation of the door locks is the same as for a system without central locking, as described in chapter 11.

2. If there is a fault in the system, check the tightness of the hoses and connections. A leak causes the pump to run for more than five seconds and the built-in control unit may shut off the system automatically.

Vacuum lock blocks

3. Refer to the information in the relevant paragraphs chapters 11.

4. The fuel filler door control is located behind the right side trim panel in the luggage compartment. It can be removed by disconnecting the hose from the positioner unit, the positioner/door control rod and unscrewing the fastening screw. Installation is the reverse procedure.

Air pump

5. Remove the left luggage compartment trim panel. Remove the pump unit on the right side (Fig. 18.5).



6. Remove the pump from the insulating housing. Disconnect the wiring connector and vacuum hoses. Remove the pump (fig. 18.6, a, b, c).






7. Installation - reverse procedure. Check the system for proper operation before installing the trim panel.