2006_C350

What exactly are these and what do they do?

1. Assist. Graphic

2. Distance Warning

2. Attention Asst.

Please see below the picture of what I'm asking about.

GregTR

User manual page 246.

#1 displays the graphic status of the various assistant modes such as attention assist, lane markings for lane keeping assist, distance warning function or PRE-SAFE Brake system

#2 Enables or disables distance warning. Info about the system is on page 70.

#3. Enables or disables attention assist which is a system that monitors driver alertness and if it detects tiredness it offers a virtual cup of java and advises you to take a break. More info is on Page 225.

2006_C350

I really don't understand the manual, and some things jump around to different pages.

What exactly does the distance warning do and when will I know it is working? Does it make a beep or noise?

GregTR

The distance warning is a system that monitors the cars in front of you and if it feels that unless you make a corrective action by slowing down or changing direction it will emit a sound and a visual warning on the dash. The system can also give false alarms in certain situations. So in normal driving you should not see or hear anything. But when you're closing in on a car or obstacle in front of you it will give you audible and visual warnings. This is what you can disable.

The system has a secondary part which is the active brake assist which will apply the brakes at the correct force regardless of foot pressure if the system detects an impeding collision. The system only works on moving cars in front of you. This helps when people recognize the danger but don't apply enough brake force on their own to stop the vehicle. This feature cannot be disabled.

If you have the $2,800 driving assistance package there are more parts to the system.

Arrie

"which will apply the brakes at the correct force regardless of foot pressure if the system detects an impeding collision"


Are you saying the car now stops behind a stopped car even if you don't hit the brakes? It used to be that it gives a warning 1.5 seconds before the impact and then applies 40% brakes if the driver does not do anything.

GregTR

There are several systems available from MB:


1) Brake Assist System
This system applies increased brake force when it detects that you depressed the brake pedal in an emergency type braking situation. It makes the determination whether it's an emergency based on the speed you moved your foot from the accelerator to the brake. All W212 comes with this system. The system will not brake automatically.

2) Collision Prevention Assist, it comes on all new W212 standard. The Collision Prevention Assist has two features:
a) Distance Warning Function. This system beeps and blinks at you if it thinks you're approaching the vehicle in front of you too fast. The system only monitors for moving vehicles and moving vehicles which came to a complete stop. It will not monitor stationary objects, pedestrians or oncoming or crossing traffic. It can be turned off.
b) Adaptive Brake Assist. This system is the secondary part of the collision prevention assist. It increases brake pressure to optimal brake pressure should you apply the brakes too lightly under an emergency braking situation. You must apply the brakes yourself, the system only increases the brake pressure should it deem it insufficient for the given situation. As the Distance Warning Function, it only responds to vehicles that were once in your path and picked up by the system as a moving vehicle.

There are more systems which only come with the car if you have the Driving Assistance package ($2,800 option).

3) Braking Assistance Plus (BAS Plus)
This system not only applies the brakes at full force when it detects that you moved your foot from the gas to the brake too fast but it will also do it automatically if it detects cross traffic or pedestrians jumping in front of you. This system is smarter than the BAS as it will apply brakes based on how closely you're closing in on the vehicle or person in front of you and it will optimize the braking distance to reduce the chance of you getting rear ended as well by maximizing your brake distance and stop you as close as possible to the car in front of you giving the person behind you more room. Again, no automatic braking takes place.

4) PRE-SAFE Brake
This is the only system that applies the brakes automatically. It will apply the brakes at up to 50% brake force automatically if it detects a rear end collision is possible without corrective action and you failed to apply the brakes on your own to reduce the impact but not completely eliminate it. It will apply up to 100% brake force once it recognizes that the crash is imminent. It can also apply 100% brake force to stop the vehicle if you're going slower than 44mph to avoid stationary objects and/or pedestrians. One more feature is that if it detects that you are about to get rear ended yourself it will brace you by pulling the seatbelts tight and applying the brakes so you car won't lurch forward upon impact.

So to summarize unless you have Distronic Plus your car will never brake on its own but it will apply increased brake pressure should you fail to apply enough brake pressure in a given situation and it will give you audible and visual warning in some instances should you opt to leave such warning on.

Here is a video demonstration of the PRE-SAFE system. This is the best description of the system and the explanation why the Mercedes system "fails" those tests that stupid magazines do with no understanding of how the system works.