Driving safety systems
Overview of driving safety systems
In this section, you will find information about the following driving safety systems:
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ABS (Anti-lock Braking System)
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BAS (Brake Assist System)
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Adaptive brake lamps
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ESP® (Electronic Stability Program)
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EBV (electronic brake-power distribution)
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4-ETS (Electronic Traction Support)
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Distance warning function* (vehicles with Distronic*)
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In wintry road conditions, always use winter tyres (M+S tyres) and, where necessary, snow chains. Only in this way will the driving safety systems described in this section work as effectively as possible.
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 | Risk of accident |
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The risk of an accident is significantly increased by driving too fast. This is particularly the case when cornering on wet and slippery roads and when driving too close to the vehicle in front.
The driving safety systems described in this section cannot reduce this risk nor override the laws of physics.
For this reason, always adapt your driving style to suit prevailing road and weather conditions. Maintain sufficient distance from other road users and objects on the road.
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ABS (Anti-lock Braking System)
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 8 km/h upwards, regardless of road surface conditions. ABS works on slippery surfaces, even when you only brake gently.
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Do not depress the brake pedal several times in quick succession (pumping). Depress the brake firmly and evenly. Pumping the brake pedal reduces the braking effect.
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Braking
If ABS intervenes when braking, you will feel a pulsing in the brake pedal.
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If ABS intervenes: continue to depress the brake pedal with force until the braking situation is over.
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To make a full brake application: depress the brake pedal with full force.
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If ABS is faulty, the wheels could lock when braking. This limits the steerability of the vehicle when braking and the braking distance may increase.
If ABS is deactivated due to a malfunction, then BAS and ESP are also deactivated. There is an increased risk of your vehicle skidding in certain situations.
You should always adapt your driving style to suit the prevailing road and weather conditions.
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Off-road ABS
An ABS system specifically suited to off-road terrain is activated automatically if the off-road drive program more is activated or if the LOW RANGE* more off-road gear is selected.
At speeds below 30 km/h, the front wheels lock cyclically during braking. The digging-in effect achieved in the process reduces the stopping distance on off-road terrain. This limits steering capability.
BAS (Brake Assist)
BAS operates in emergency braking situations. If you depress the brake pedal quickly, BAS automatically boosts the braking force, thus shortening the stopping distance.
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Keep the brake pedal firmly depressed until the emergency braking situation is over.
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ABS prevents the wheels from locking.
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The brakes will function as usual once you release the brake pedal. BAS is deactivated.
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If BAS has malfunctioned, the braking system remains available with full brake boosting effect. However, braking force is not automatically increased in emergency braking situations and the stopping distance may increase.
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Adaptive brake lamps
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Adaptive brake lamps are only available in certain countries.
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If you brake sharply from a speed of more than 25 km/h or if braking is assisted by BAS, the brake lamps flash rapidly. In this way, traffic travelling behind you is warned in an even more noticeable manner.
If you brake sharply from a speed of more than 70 km/h to a standstill, the hazard warning lamps are activated automatically. If the brakes are applied again, the brake lamps light up continuously. The hazard warning lamps switch off automatically if you drive faster than 10 km/h again. You can also switch off the hazard warning lamps using the hazard warning switch button more.
ESP® (Electronic Stability Program)
ESP® monitors driving stability and traction, i.e. power transmission between tyres and the road surface.
If ESP® detects that the vehicle is deviating from the direction desired by the driver, one or more wheels are braked to stabilise the vehicle. The engine output is also modified, if necessary, 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 stabilise the vehicle during braking.
When ESP® intervenes, the 
warning lamp flashes in the instrument cluster.
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If the warning lamp in the instrument cluster flashes, proceed as follows:
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do not deactivate ESP® under any circumstances.
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only depress the accelerator pedal as far as necessary when pulling away.
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adapt your driving style to suit prevailing road and weather conditions.
The vehicle could otherwise go into a skid.
ESP® cannot reduce the risk of an accident if you drive too fast. ESP® cannot override the laws of physics.
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Only operate the vehicle briefly (for a maximum of ten seconds) on a brake dynamometer. Turn the key in the ignition lock to position 0 or 1. You could otherwise damage the drive train or the brake system.
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A function or performance test should only be carried out on a twin-axle dynamometer. If you wish to operate the vehicle on such a dynamometer, please consult a Mercedes-Benz Service Centre in advance. You could otherwise damage the drive train or the brake system.
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Only use wheels with the recommended tyre sizes. Only then will ESP® function properly.
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ESP® trailer stabilisation
If your trailer begins to lurch, you can only stabilise the vehicle/trailer combination by depressing the brake firmly.
In this situation, ESP® assists you and detects if the trailer begins to lurch. ESP® slows the vehicle down by braking and limiting the engine output so the vehicle/trailer combination can stabilise.
Trailer stabilisation is active from about 65 km/h.
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If road and weather conditions are bad, trailer stabilisation will not be able to prevent the trailer from swerving and thereby reduce the risk of accident. Trailers with a high centre of gravity can tip over before ESP® can detect this.
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Trailer stabilising does not work if ESP® is deactivated or disabled because of a malfunction.
Activating/deactivating ESP®
ESP® is activated automatically when the engine is running.
It may be best to deactivate ESP® in the following situations:
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when using snow chains
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in deep snow
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on sand or gravel
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Activate ESP® as soon as the situations described above no longer apply. ESP® will otherwise not be able to stabilise the vehicle if the vehicle starts to skid or a wheel starts to spin.
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If you deactivate ESP®:
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ESP® no longer improves driving stability.
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the engine's torque is no longer limited and the drive wheels can spin. Spinning of the wheels results in a cutting action, which provides better grip.
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traction control is still activated.
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ESP® still provides support when you brake.
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If ESP® is deactivated and one or more wheels start to spin, the warning lamp in the instrument cluster flashes. In such situations ESP® will not stabilise the vehicle.
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 | To deactivate/activate ESP® |
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To deactivate: press button .
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The warning lamp in the instrument cluster lights up.
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If the warning lamp in the instrument cluster is continuously lit when the engine is running, ESP® is deactivated or not available due to a malfunction. There is an increased risk of your vehicle skidding in certain situations.
You should always adapt your driving style to suit prevailing road and weather conditions.
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To activate: press button .
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The warning lamp in the instrument cluster goes out.
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Off-road ESP®
An ESP® system specifically suited to off-road terrain is activated automatically if the off-road drive program is activated more or if the LOW RANGE* off-road gear is selected more. It intervenes with a delay if there is oversteering or understeering, thus improving traction.
EBV (electronic brake-power distribution)
EBV monitors and controls the brake pressure on the rear wheels to improve driving stability under braking.
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If EBV is malfunctioning, the brake system is still 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.
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4ETS
4-ETS makes it possible to pull away or accelerate on a slippery surface. It brakes the wheels individually if they start to spin.
The warning lamp in the instrument cluster lights up briefly when the engine is started. This indicates that the warning lamp is operational.
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Activate the off-road drive program more or the LOW RANGE* off-road gear more if appropriate to driving conditions.
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The warning lamp in the instrument cluster flashes at any speed if at least one tyre has exceeded its tyre grip limit.
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If the warning lamp in the instrument cluster flashes, proceed as follows:
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Only depress the accelerator pedal as far as necessary when pulling away.
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Accelerate less when driving.
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Adapt your driving style to suit prevailing road and weather conditions.
The vehicle could otherwise go into a skid.
If you drive too fast, 4-ETS cannot reduce the risk of an accident. 4-ETS cannot override the laws of physics.
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Only operate the vehicle briefly (for a maximum of ten seconds) on a brake dynamometer. Turn the key in the ignition lock to position 0 or 1. You could otherwise damage the drive train or the brake system.
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A function or performance test should only be carried out on a twin-axle dynamometer. If you wish to operate the vehicle on such a dynamometer, please consult a Mercedes-Benz Service Centre in advance. You could otherwise damage the drive train or the brake system.
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If heavy demands are made on the brakes, 4-ETS switches off automatically for a brief period so that the brakes do not heat up further. If, for this reason, 4-ETS does not engage, the warning lamp in the instrument cluster lights up. The message ABS, ESP unavailable see Owner's Manual also appears in the multi-function display.
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The engine may be switched on when the vehicle is towed with its axle raised or when the parking brake is checked on the brake dynamometer. Application of the brakes via 4-ETS may otherwise destroy the brake system.
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Off-road 4-ETS
A 4-ETS system specifically suited to off-road terrain is activated automatically if the off-road drive program is activated more or the LOW RANGE* off-road gear is selected more.
Distance warning system (only for vehicles with Distronic*)
This function will issue a warning at speeds of around 30 km/h or more if:
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for a period of several seconds, the distance to the vehicle in front is too short for the speed at which you are travelling. The distance warning lamp 
in the instrument cluster will then light up.
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you are approaching the vehicle in front too rapidly. An intermittent warning tone will then sound and the distance warning lamp will light up in the instrument cluster.
In order to maintain the appropriate distance to the vehicle in front and thus prevent a crash, you must apply the brakes yourself.
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Pay particular attention to the traffic conditions if the distance warning lamp in the instrument cluster lights up or an intermittent warning tone sounds.
If necessary, brake or swerve to avoid an obstacle.
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To activate/deactivate: activate or deactivate the distance warning system in the on-board computer more.
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After activation, the  symbol is displayed in the lower multi-function display.
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For more information on the distance warning system, see the Distronic* section more.
