Electronic Differential Lock. If you can imagine it works similar to a limited slip diff to stop inside wheel spin and help the car corner.
From wikipedia
Traction control systems are also used in many modern vehicles either in addition or as a replacement of locking differentials. One example is that offered by Volkswagen under the name of electronic differential lock (EDL). This EDL is not in fact a differential lock, but operates at each wheel. Sensors monitor wheel speeds, and if one is rotating more than 100 RPM more than the other (i.e. slipping) the EDL system momentarily brakes it. This effectively transfers all the power to the other wheel,[2] but still employs the open differential, which is the same as on cars without the EDL option. Electronic traction control systems may be integrated with anti-lock braking systems, which have a similar action on braking and use some similar components. Such systems are used for example on the most recent Nissan Pathfinder, Land Rover Defender and Land Rover Freelander models.
