Differential lock mechanism (Audi A4 B5)

While the previous Audi 80 model was still equipped with a mechanical rear axle lock, the A4 uses the EDS system to lock. Its advantage is that the lock also affects the front wheels, but it has the disadvantage that the locking effect is achieved only by braking the rotating wheel, which is less effective under certain operating conditions than with a mechanical lock.

The EDS system is closely related to the anti-lock braking system, so for technical information on EDS, please read the section ABS and EDS.