Collision prevention assist
 

does this function even work. I tried to get close to a car and nothing. My front bumper has no sensors but I don't think it works off of sensors.

Anyone have any issues with this.

No display warning or beeps when approaching a car too quickly? Something must be wrong. You are in active moving traffic, correct? Trying to approach someone too quickly, right? Not just pulling up behind someone at a stoplight and seeing if it will trigger a warning. Right? It's a very intelligent system using cameras to monitor positions.

Do you have Distronic?

Every time I've tried "induce" the warning intentionally, I've had no luck. However, one time on the highway the car in front of me suddenly started braking heavily and I didn't notice immediately. The system gave a pretty attention grabbing audio warning. The warning definitely caught my attention and I was able to slam on the breaks before impact. Definitely saved me and i don't honestly know what would have happened without the warning.

I believe the system is designed so that you get the fewest possible number of false warnings. It calculates the closing speed between the two vehicles and sounds the alarm when a collision is imminent. Someone may have a more accurate/technical description. In cars without distronic, I believe the radar sensor is behind the rearview mirror.

no but you shouldn't need disctronic.

I may have figured it out but haven't tried it yet. DO YOU NEED TO HAVE YOUR SEATBELT ON

I don't have distronic in my car and mine works. I always wear my seat belt so I can't answer that part. Here is the best way I have found to test it. Find a two lane road where someone is making a left turn. Make sure the right lane is clear then follow behind the car that is turning and as he slows down kinda make your way to the right lane so as to just barley (use extreme caution) pass to the right of him. Your car should give you an audible beep as well as a visual symbol on the instrument cluster that you are approaching an object (car) too quickly. Again, use caution.

bump. didn't work.

Hmmmm....what year is your e350?

2016

Strange, it should work. I have a 2014 E550 and it works in mine. The new model E class didn't come out till 2017 so we should both have the same systems. I noticed if I pull into my driveway and approach my
garage door too quick it also goes off. You need to try to approach a stationary object at a high speed to "test it" without crashing into it. Don't know if the dealer can diagnose this and make sure it's working properly.

Take it to the dealer and have them hook up to SDS. Something is wrong with your car.

I was in a bumper to bumper traffic on I405 as my lane cleared up enough to accelerate to about 40+mph some idiot move into my lane. My foot was still on the accelerator but the car hit the brake on it own, something lid up on the dash as I was to pissed off to take notice what it was. I try so many time to recreate what just happen but it never work. I guess the car know the different between a real and fake collision.

When I get time I will try to create a collision in a controlled environment. I have two patio umbrella stand that I can hang a dark beach towel across two broom stick. I want know if the MB collision really work or if it just intermitting.

FWIW, the 2017 C300 loaner vehicle did made that sound. Same with GLA 250 Loaner too.

That's a nice idea, also, someone mentioned using refrigerator cardboard boxes also will work in the same way.

Funny that you mention that, the 2017 GLC 300 loaner I have has it, but under settings, DriveAssist there is a way to shut it off. Don't think it is possible with the W212 models though.

Yes, you can absolutely turn off the distance warning function, or the Pre-Safe brake function if you have Distronic.
It's in the multi function display. If the OP has this function turned off, we have wasted a lot of time here.

Key08 I think the OP stated he didn't have Distronic in this thread. I don't have my car so I can't look in the MDF display to see if us non-distronic owners can shut this feature off. Won't know until I get my car back Monday night.

The distance warning function is separate from Distronic.This is the warning he is not receiving form my understanding.The Pre-safe Brake is ONLY found on cars with Distronic.

I believe collision prevention assist is standard on all E class. Once I didn't step on the brake to slow down fast enough for a traffic light with park traffic ahead, the alarm when off. Probably was moving like 25 mph as I coast closer to the stop vehicle ahead.
http://techcenter.mercedes-benz.com/...st/detail.html

For those with distronics
http://techcenter.mercedes-benz.com/...us/detail.html

I think mine kicked in this afternoon backing into the driveway. There was no alarm but car came to a sudden stop. I was still about 3 to 4 feet from the garage door. This is on a 2016 wagon

Did you open the drivers door to get a better view while backing up? The car will stop itself when you open the door.

That might have been it. That would explain the alarm not going off?

Still not used to all the tech on the car. :)

Did the experiment over the weekend in an empty parking lot and I can confirm it does work only in certain conditions. like when speed have to be over 30+ mph and your foot have to be depressing the accelerator. I try coasting through and it does not work. I did about a dozen tries with and without depressing the accelerator and pressing it work every time. Keep in mind how well your car stop depending on good your brake are. If your brake is worn it will not stop as well as a new car. There were a few time when the car went right thought the towel before it come to a complete stop. :eek:

As soon as I know how to get the video off my phone I will post of video.

Pette25,
I absolutely get where you are coming from: I though the same thing about my car for the first 2 months of ownership. Took it to the dealer and they "assured me everything was functioning properly," even though I never got the warning when I tried to create scenarios and force it to intevene.

I will say this, it *may* depend on how often you drive your car and other factors. I did/do not drive my car much and many of my systems seemed to not work. I believe this system may be controlled by the auxiliary battery, as is the ECO function. The reason I say this is because my ECO engine shut-off function also didn't work...but the moment I drove my car long distances, I noticed my ECO lit up green on the dash and the engine turned off at stops.

So the two may be related...just a thought.

Do you drive your car long enough for it to charge the aux battery? If my theory proves right, then that is a major design flaw: the system only works if the aux battery is charged enough. ---->well, what if a car pulls out in front of me as soon as I exit my sub-division???? :eek:

My BMW's system actually has two selectable stages of warning (early and late), and will actually apply the brakes for you if a crash is imminent. Gives me much more piece of mind than the Mercedes system.

I can confirm that this system does not work on auxiliary battery as I only drive around 12-15 miles a day on weekdays. My ECO stop won't work during my drive to/back from work. ECO stop does work when I drive much longer distance on weekends to charge the battery.

Earlier today I did trigger another alarm with the red triangle light light up next to the ESP light, just above the left turn signal light. Here is how I trigger it. I was following a car with like 5 car length and it was start to turn left slowly at a intersection. I didn't bother to step on the brake on the car since I was traveling around 25-30 mph. As it get to like 3 car length the alarm went off. (beep beep) with the red triangle light on dash. Once the car disappear ahead, the alarm went off and light disappeared.

Sometime I have to search on which alarm is going off. Is it blind spot, parktronic distance, or etc. Wish there was a message on the Multifunction display.