Driving safety systems

Driving safety systems overview

In this section, you will find information about the following driving safety systems: - ABS (Anti-lock Braking System) - BAS (Brake Assist System) - BAS PLUS (Brake Assist System Plus*) - ESP® (Electronic Stability Program) - EBD (Electronic Brake force Distribution) - ADAPTIVE BRAKE
- PRE-SAFE® Brake
- Steering assistant STEER CONTROL

Important safety notes

If you fail to adapt your driving style, the driving safety systems can neither reduce the risk of accident nor override the laws of physics. Driving safety systems are merely aids designed to assist driving. You are responsible for the distance to the vehicle in front, for vehicle speed and for braking in good time. Always adapt your driving style to suit the prevailing road/weather conditions, as well as the traffic conditions and maintain a safe distance to the vehicle in front. Drive carefully.

Please note that the driving
safety systems described only work as effectively as possible when there is adequate contact between the tires and the road surface. Pay particular attention to the information regarding tires, recommended minimum tire tread depths etc. in the "Wheels and tires" section.

In wintry driving conditions, always use winter tires (M+S tires) and if necessary, snow chains. Only in this way will the driving safety systems described in this section work as effectively as possible.

ABS (Anti-lock Braking System)

Important safety notes

Observe the "Important safety
notes" section.

ABS regulates brake pressure in such a way that the wheels do not lock when you brake.

This allows you to continue steering the vehicle when braking.

ABS works from a speed of about 5 mph(8 km/h) upwards, regardless of roadsurface conditions. ABS works on slippery surfaces, even when you only brake gently.

WARNING
If the ABS malfunctions, other driving systems such as the BAS or the ESP® are also switched off. Observe indicator and warning lamps that may come on as well as messages in the multifunction display that may appear.

If the ABS malfunctions, the wheels may lock during hard braking, reducing the steering capability and extending the braking distance.

The warning lamp in the
instrument cluster lights up when the ignition is switched on. It goes out when the engine is running.

Braking

If ABS intervenes when braking, you will feel a pulsing in the brake pedal.

- If ABS intervenes: continue to depress the brake pedal with force until the braking situation is over.

- To make a full brake application:

depress the brake pedal with full force.

The pulsating brake pedal can be an indication of hazardous road conditions, and functions as a reminder to take extra care while driving

WARNING
Do not pump the brake pedal. Use firm, steady brake pedal pressure instead. Pumping the brake pedal defeats the purpose of the ABS and significantly reduces braking effectiveness.

BAS (Brake Assist System)

Observe the "Important safety
notes" section.

BAS operates in emergency braking situations. If you depress the brake pedal quickly, BAS automatically boosts the braking force, thus shortening the stopping distance.

- Keep the brake pedal firmly depressed until the emergency braking situation is over.

ABS prevents the wheels from locking.

The brakes will function as usual once you release the brake pedal. BAS is deactivated.

WARNING
If the BAS malfunctions, the brake system still functions, but without the additional brake boost available that the BAS would normally provide in an emergency braking maneuver.

Therefore, the braking distance may increase.

BAS PLUS (Brake Assist System Plus)

BAS PLUS is only available in vehicles equipped with DISTRONIC PLUS.

Observe the "Important safety
notes" section.

At speeds above approximately 20 mph (30 km/h), BAS PLUS assists you when braking in hazardous situations and uses the radar sensor system to evaluate the traffic conditions.

This device has been approved by
the FCC as a "Vehicular Radar System". The radar sensor system is intended for use in an automotive radar system only. Removing, altering or tampering with 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.

With the help of the radar sensor system, BAS PLUS can detect obstacles that are in the path of your vehicle for an extended period of time.

At speeds up to approximately 40 mph (70 km/h), BAS PLUS can also detect stationary obstacles, for example stopped or parked vehicles.

Should you approach an obstacle and BAS PLUS has detected a risk of collision, BAS PLUS calculates the braking force necessary to avoid a rear-end collision. Should you apply the brakes forcefully, BAS PLUS can automatically increase the braking force to a level suitable for the traffic conditions.

- Keep the brake pedal depressed until the emergency braking situation is over.

ABS prevents the wheels from locking.

The brakes will work normally again if: - you release the brake pedal.

- there is no longer any danger of a rear-end collision.

- no obstacle is detected in front of your vehicle.

BAS PLUS is then deactivated. If you have activated DSR, BAS PLUS is likewise deactivated.

For BAS PLUS to assist you when driving, the radar sensor system must be switched on and operational, see "Radar sensor system" in the index.

WARNING
BAS PLUS cannot always clearly identify objects and complex traffic situations. BAS PLUS cannot intervene in these cases.

There is a risk of an accident. Always pay careful attention to the traffic situation and be ready to brake.

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
BAS PLUS does not react: - to people or animals
- to oncoming vehicles
- to crossing traffic
- in curves
As a result, BAS PLUS 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.

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.

If BAS PLUS is not available due to a malfunction in the radar sensor system, the brake system remains available with full brake boosting effect and BAS.

ESP® (Electronic Stability Program)

Important safety notes

See the "Important safety notes"
section.

If ESP® detects that the vehicle is deviating from the direction desired by the driver, one or more wheels are braked to stabilize the vehicle. If necessary, the engine output is also modified to keep the vehicle on the desired course within physical limits. ESP® assists the driver when pulling away on wet or slippery roads. ESP® can also stabilize the vehicle during braking.

If ESP® intervenes, the ESP®
warning lamp flashes in the instrument cluster.

WARNING
Under no circumstances should you deactivate ESP® when the

ESP® warning lamp in the instrument cluster flashes. Proceed as follows:

Rwhen driving off, apply as little throttle as possible.

Rwhile driving, ease up on the accelerator pedal.

Radapt your speed to suit the prevailing road and weather conditions.

Failure to observe these guidelines could cause the vehicle to skid. ESP® cannot prevent accidents resulting from excessive speed.

Only operate the vehicle for
a maximum of ten seconds on a brake test dynamometer. Switch off the ignition.

Application of the brakes by ESP® may otherwise destroy the brake system.

Function or performance tests
may only be performed on a 2-axle dynamometer. If you wish to operate the vehicle on such a dynamometer, please consult an authorized Mercedes-Benz Center beforehand. You could otherwise damage the drive train or the brake system.

Only use wheels with the
recommended tire sizes. Only then will ESP® function properly.

4ETS (Electronic Traction System)

Observe the "Important safety
notes" section.

Traction control is part of ESP®.

Traction control brakes the drive wheels individually if they spin. This enables you to pull away and accelerate on slippery surfaces, for example if the road surface is slippery on one side. In addition, more drive torque is transferred to the wheel or wheels with traction.

Traction control remains active if you deactivate ESP®.

WARNING
Traction control cannot reduce the risk of an accident if you drive too fast. Traction control cannot override the laws of physics.

Deactivating/activating ESP®

Observe the "Important safety
notes" section.

WARNING
ESP® should not be deactivated during normal driving other than in the circumstances described below. Disabling the system will reduce vehicle stability in driving maneuvers.

Do not deactivate ESP® when the emergency or spare wheel is mounted.

ESP® is activated automatically when the engine is started.

It may be best to deactivate ESP® in the following situations:
- when using snow chains - in deep snow
- on sand or gravel

WARNING
Switch on ESP® immediately if one of the previously stated conditions is no longer met.

Otherwise, ESP® cannot stabilize the vehicle if it begins to lurch or when a wheel spins.

When you deactivate ESP®: - ESP® no longer improves driving stability.

- the engine's torque is no longer limited and the drive wheels can spin. The spinning of the wheels results in a cutting action, which provides better grip.

- traction control is still activated.

- ESP® still provides support when you brake.

If ESP® is deactivated and one or more wheels start to spin, the ESP® warning
lamp in the instrument cluster flashes. In such situations, ESP® will not stabilize the vehicle.

- To deactivate: press button 1.

The ESP® OFF warning lamp in the
instrument cluster lights up.

WARNING
When the

ESP® OFF warning
lamp is lit, ESP® is deactivated.

If the

ESP® warning lamp and
the

ESP® OFF warning lamp remain
lit, ESP® is not available due to a malfunction.

When ESP® is deactivated or not operational, vehicle stability in standard driving maneuvers is reduced.

Adapt your speed and driving to the prevailing road conditions and to the non-operating status of the ESP®.

Avoid spinning the driven
wheels for an extended period with ESP® deactivated.

You could otherwise damage the drivetrain.

- To activate: press button 1.

The ESP® OFF warning lamp in the
instrument cluster goes out.

ESP® trailer stabilization

If your vehicle with trailer (vehicle/trailer combination) begins to lurch, you can only stabilize the vehicle/trailer combination by depressing the brake firmly.

In this situation, ESP® assists you and can detect if the vehicle/trailer combination begins to lurch. ESP® slows the vehicle down by braking and limiting the engine output until the vehicle/trailer combination has stabilized.

Trailer stabilization is active from a speed of approximately 37 mph(60 km/h).

WARNING
The system will not be able to assist when the trailer jackknifes
- if the ESP® has switched off due to a malfunction
- on wet or icy roads
- on roads with slippery surface - in sand or gravel
Trailers with a high center of gravity may tip over before the system recognizes swaying of the trailer.

Trailer stabilization does not work if ESP® is deactivated or disabled because of a malfunction.

EBD (electronic brake force distribution)

Observe the "Important safety
notes" section.

EBD monitors and controls the brake pressure on the rear wheels to improve driving stability while braking.

WARNING
If EBD has malfunctioned, the braking system remains available with full brake boosting effect. However, the rear wheels can still lock, e.g. under full braking. This could cause you to lose control of your vehicle and cause an accident. You should therefore adapt your driving style to the different handling characteristics.

- Observe the notes on warning and indicator lamps as well as display messages.

ADAPTIVE BRAKE

ADAPTIVE BRAKE enhances braking safety and offers increased braking comfort. In addition to the braking function, ADAPTIVE BRAKE also has the HOLD function and hill start assist. For further information, see Driving tips.

PRE-SAFE® Brake

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.

At speeds of above approximately 20 mph (30 km/h), if the driver and front passenger have fastened their seat belts, PRE-SAFE® Brake can:
- brake the vehicle automatically at speeds up to approximately 124 mph (200 km/h) - trigger preventative occupant protection measures (PRE-SAFE®)

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.

If you have activated DSR, PRESAFE ® Brake is deactivated.

USA only: this device has been
approved by the FCC as a "Vehicular Radar System".

The radar sensor system is intended for use in an automotive radar system only.

Removing, altering or tampering with 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 there is an increased risk of collision, preventative passenger protection measures (PRE-SAFE®) are activated (Y page 49). 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 Active Parking Assist, 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.

STEER CONTROL

The steering assistant STEER CONTROL helps you by transmitting a noticeable steering force to the steering wheel in the direction required for vehicle stabilization.

This steering assistance is provided in particular if:
- both right wheels or both left wheels are on a wet or slippery road surface when you brake
- the vehicle starts to skid You have control over the steering at all times.

WARNING
If the ESP® is malfunctioning, you will not receive steering assistance from the STEER CONTROL. The power steering function, however, remains available.