This feature enables you to stop the vehicle if the main brake system should fail or if the pedal is obstructed.
To stop the vehicle with the parking brake in an emergency, pull and hold the 
switch.
switch.The brakes will be released immediately if you release the switch or press the accelerator.
switch or press the accelerator.If you pull out and hold the switch at a road speed above about 8 km/h, this will initiate an emergency brake application. The brakes are then applied hydraulically at all four wheels. The effect is similar to heavy braking WARNING!.
switch at a road speed above about 8 km/h, this will initiate an emergency brake application. The brakes are then applied hydraulically at all four wheels. The effect is similar to heavy braking WARNING!.To prevent the emergency braking function from being used accidentally, a warning buzzer sounds when the switch is operated. The brakes are released immediately when you release the switch or press the accelerator.
switch is operated. The brakes are released immediately when you release the switch or press the accelerator.You should only use the emergency braking function in a real emergency, for example if the brake system were to fail or if the brake pedal were to be obstructed. If you use the emergency braking function by activating the parking brake switch, this has the same effect as heavy braking. Please remember that the ESC (with its combined ABS, EDL and traction control functions) is still subject to certain physical limits. In a corner or in bad road or weather conditions an emergency stop can cause the vehicle to skid or lose steering control.