PRE-SAFE® Brake is only available in vehicles with DISTRONIC PLUS.

Observe the "Important safety notes" section.

PRE-SAFE® Brake can help you to minimize the risk of a frontal collision with a vehicle ahead or reduce the effects of such a collision. If PRE-SAFE® Brake has detected a risk of collision, you will be warned visually and acoustically as well as by automatic braking. PRE-SAFE® Brake cannot prevent a collision without your intervention.

At speeds above approximately 20 mph (30 km/h), this function warns you when you are rapidly approaching the vehicle in front. An intermittent warning tone will then sound and the distance warning lamp in the instrument cluster will light up.

Brake immediately in order to increase the distance from the vehicle in front.

or

Take evasive action provided it is safe to do so.

If the driver and front passenger have their seat belt fastened, PRE-SAFE® Brake can also brake the vehicle automatically at speeds from approximately 20 mph (30 km/h) to approximately 124 mph (200 km/h).

Due to the nature of the system, particularly complicated driving conditions may cause unnecessary warnings or the unnecessary intervention of PRE-SAFE® Brake. To stop the braking action, you can either depress the accelerator pedal further, activate kickdown or release the brake pedal.

The braking action of PRE-SAFE® Brake is ended automatically if:
• your speed drops below approximately 9 mph (15 km/h).
• you maneuver to avoid the obstacle.
• there is no longer any danger of a rear-end collision.
• there is no longer an obstacle detected in front of your vehicle.

USA only: this device has been approved by the FCC as a "Vehicular Radar System".
The radar sensor is intended for use in an automotive radar system only. Removal, tampering, or altering of the device will void any warranties, and is not permitted by the FCC. Do not tamper with, alter, or use in any non-approved way.
Any unauthorized modification to this device could void the user's authority to operate the equipment.

Canada only: this device complies with RSS-210 of Industry Canada. Operation is subject to the following two conditions:
1. This device may not cause interference, and
2. this device must accept any interference received, including interference that may cause undesired operation of the device.
Removal, tampering, or altering of the device will void any warranties, and is not permitted. Do not tamper with, alter, or use in any non-approved way.
Any unauthorized modification to this device could void the user's authority to operate the equipment.

With the help of the radar sensor system, PRE-SAFE® Brake can detect obstacles that are in front of your vehicle for an extended period of time.

At speeds up to approximately 40 mph (70 km/h), PRE-SAFE® Brake can also react to stationary obstacles, for example stopped or parked vehicles.

If you approach an obstacle and PRE-SAFE® Brake detects a risk of collision, the system will initially alert you both visually and acoustically. If you do not brake or take evasive action, the system will warn you by automatically braking the vehicle gently. If the risk of collision remains and you do not brake, take evasive action or accelerate significantly, the vehicle may perform automatic emergency braking. Automatic emergency braking is not performed until immediately prior to an accident that can no longer be avoided.

WARNING
Even if PRE-SAFE® Brake slows the vehicle before an imminent rear-end collision, the system cannot avert a collision without the intervention of the driver. There is a risk of an accident. Brake according to the situation or take evasive action. Delayed intervention by the driver can lead to an accident.

WARNING
PRE-SAFE® Brake cannot always detect complex traffic situations properly.
In these cases, PRE-SAFE(R) Brake may:
• give an unnecessary warning and then brake the vehicle
• neither give a warning nor intervene
There is a risk of an accident. Always pay particular attention to the traffic situation and be ready to brake, especially if PRE-SAFE(R) Brake warns you. Terminate the intervention in a non-critical driving situation.

In particular, the detection of obstacles can be impaired if there is:
• dirt on the sensors or anything else covering the sensors
• snow or heavy rain
• interference by other radar sources
• the possibility of strong radar reflections, for example in parking garages
• a narrow vehicle traveling in front, e.g. a motorbike
• a vehicle traveling in front on a different line

WARNING
PRE-SAFE® Brake does not react:
• to people or animals
• to oncoming vehicles
• to crossing traffic
• in curves
As a result, PRE-SAFE® Brake cannot intervene in critical situations. There is a risk of an accident. Always pay careful attention to the traffic situation and be ready to brake.

In order to maintain the appropriate distance to the vehicle in front and thus prevent a collision, you must apply the brakes yourself.

  To activate/deactivate: activate or deactivate PRE-SAFE® Brake in the onboard computer.
The symbol appears in the multifunction display as long as the HOLD function is not activated.
On vehicles with Parking Guidance, the symbol is displayed when transmission position P is selected or if you drive faster than 22 mph (35 km/h).

For PRE-SAFE® Brake to assist you when driving, the radar sensor system must be switched on and operational.

Following damage to the front end of the vehicle, have the configuration and operation of the radar sensors checked at a qualified specialist workshop. This also applies to collisions at low speeds where there is no visible damage to the front of the vehicle.