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.

OP,

I finally got my car back and had a chance to look over the settings. In Non-Distronic cars go to DriveAssist on your Multi Function Display and go down to Distance Warning and make sure it says “Enabled” now that you are sure the assist is activated, try the steps as other members have suggested above. I literally got 1/4 mile from the dealer after picking up my car and while I was driving and trying to connect my iPhone and not paying attention, a car stopped in front of me and I got the red triangle on the dash and audio warning alerting me to stop.

So, here's some information that may help:

Sensors: If your car is equipped with Distronic Plus: You have three radar sensors in the front of the vehicle: one in the radiator grille (long-distance unit) and two behind the front bumper. (There are three more radars in the rear bumper, but those serve different purposes including blind spot monitoring and rear collision detection.) If you have Distronic Plus, it also integrates the stereo camera data (2014+ vehicles) to factor in pedestrian detection and some other fringe cases where the radar units may not be detecting the situation appropriately (such as cross-traffic.) If your car is NOT equipped with Distronic Plus, you have one radar unit behind your front bumper, not sure if it's on the left or right side.

Actions: 2015+ vehicles can detect the collision and apply brakes autonomously. 2014 vehicles only warn and prime the brakes. If you have Distronic Plus, due to the additional two radar units, your vehicle can detect potential collisions farther away and at higher speeds. It can also detect stationary objects at higher speeds. I believe PRE-SAFE/Collision Prevention Assist Plus on DTR+ vehicles can operate up to 120MPH or so.

Testing: A towel or cardboard boxes will NOT work. You need a radar-reflective material. I have built a few test rigs of my own to test out the vehicle's capabilities. It takes some time investment to build. You can use cardboard boxes or poster boards as a starting material, but you'll need several layers of aluminum foil as a radar reflective material. The radar units will see right through the cardboard otherwise, and correctly assume that there is no threat to the vehicle. The carboard box(es) or posterboard must be about the width of a car for optimal detection. If you cover it in a few layers of foil and mount it on a stand that can be knocked over without damaging your vehicle, you've built a functional test stand.

When you do test it, drive around the block first, then stop about 30 feet from it. Your vehicle, if equipped with DTR+, should show a car ahead of you. From there, you can accelerate gradually to about 10-15MPH, and the warning should start to go off when you are about 1.5-2 seconds from collision. Braking begins at 0.6 seconds prior to collision, and should stop you just before you hit the test assembly.

I've tried this with my wife's GLK250BT, and my E250BT. The systems work flawlessly, and have saved us before, including while my wife was pregnant. Drive as if you don't have them, but man, when you need them, they can really be a life saver.

Thank you for sharing such an awesome level of detail with us all! :y

Today's radar technology is amazing, but I absolutely believe that the system will not pick up towels or cardboard boxes like you said. However, modern "consumer grade" boat radars will pick up a one to two foot tall PVC pipe sticking up from water ( at 3:35), but like you said, I would assume our car radars have an algorithm that seeks for the shape/reflection pattern of a car (or motorcycle?). At least my distronic plus seems to pick up a motorcycle, but maybe the cameras are aiding the radar at that point?

I don't understand some owners having problem with it.
My 2014 beeps about 5 times on each drive. I did not know about priming the brakes, but I used accelerator pedal instead.
The beeps usually happen when I pass slow traffic on exit lane and have short distance for merging.

same for me

Glad to do so! I'm a bit of a fanatic about this technology. So, with respect to motorcycles, yes, it's a dense, radar-reflective surface, and large enough that Distronic Plus will see it. I believe that the manual has a disclaimer about motorocycles or smaller vehicles like bicycles, but the radars still seem to see them just fine.

The boating examples are a bit easier - there's less to filter on boat radar, as basically anything that comes up in the path of the vessel is a threat and needs to be avoided. Also, more importantly, the boat works with a human in the loop to interpret the data and weed out false positives. Because roads have turns and complex environments, the algorithms that work on the car need to be a lot more selective about what they report and act upon. As they need to work without human intervention, filtering and eliminating false positives is very important.

Thanks for the explanation, but I think the part where I marked at Bold is not entirely correct??

I have a MY2014 E350T and it states the following:
266 DISTRONIC PLUS CROSS SUPPORT (DTR+Q)
268 EXPANDED BRAKE ASSIST (BAS+)
269 BRAKE ASSIST PLUS CROSS TRAFFIC (BAS+Q)
271 AUTONOMOUS BRAKE INTERVENTION/WARN. FOR PED. PROT.
300 COLLISION MINIMIZATION BRAKE INTERV./WARNING (CMS)
238 ACTIVE LANE KEEPING ASSIST (FAP)
253 REAR-END COLLISION WARNING AND PROTECTION SYSTEM

Anyway... thanks for the info!! :-)

I have that code 271 in my 2014 E550 as well, but I believe the autonomous braking part relates only to speeds below 35, where Distronic Plus will indeed follow the car directly in front of you and slow to a complete stop, while also accelerating completely on its own to your set speed. It will repeat this over and over in Stop and Go traffic so you can read the newspaper and play Sudoku while texting your boss.

1. Under 20mpg, no human intervention is required.
2. at stop and go traffic, if the car in front of you is stopped for more than 5 seconds, you need to accelerate to start the vehicle moving. But when ECO mode is active, and the engine is turned off during this stop, it'll start the vehicle(when the vehicle in front of you moves away) for you but will not move until you give some gas.

According to the Owners Manual, DISTRONIC can only apply a maximum of 50% "braking force." In the crazy SoCal traffic, I've been cruising down I-5 with Distronic engaged with the my car following traffic at around 75-80 mph when the car in front started braking extremely heavily. At that point (and to my surprise!) Distronic disengaged and gave a warning sound. This meant that the braking power required exceeded Distronic's ability of 50% of available "braking power." At that point, I needed to brake manually. If you don't start braking manually in time or don't brake hard enough, the COLLISION PREVENTION ASSIST PLUS functionality kicks in. In other words, you'll get a second visual and audible warning (first was from Distronic disengaging). If the system determines that a collision is still likely to occur, then it will start braking autonomously.

In other words, the sequence can be this if the traffic stops suddenly while DISTRONIC is engaged: 1) Distronic disengages and warns the driver with a sound and visual warning. 2) Driver is supposed to manually break to prevent collision 3) If collision is still imminent, COLLISION PREVENTION ASSIST PLUS gives an audible and visual warning 4) If driver still fails to brake, autonomous braking will (hopefully!) be applied.

Here are the quotes from the manual (I have witnessed the first part, not the second part):

"DISTRONIC PLUS brakes your vehicle with up to 50% of the maximum possible deceleration. If this braking force is insufficient, DISTRONIC PLUS warns you visually and audibly. There is a risk of an accident. In such cases, apply the brakes yourself and try to take evasive action. "

"If COLLISION PREVENTION ASSIST PLUS detects that there is a risk of a collision, you will be warned visually and acoustically. If you do not react to the visual and audible collision warning, autonomous braking can be initiated in critical situations."

I remember seeing some suggestions in the past how to test Collision Assist Plus with cardboard boxes or such, but did anyone actually try to test it?
I see that system can be disadvantage. I drive often in heavy traffic and have to cut between the cars with small clearances. The system beeps on me quite often, but would hate to be surprised if it pushed brakes in such moment.
That did not happen so far, but what are the limits?

I have a 2016 without Distronic and mine works. You mention your car does not have bumper sensors. Mine has 6 in each bumper. But I also have Parktronic.

Dealer time, hopefully under warranty.

253 REAR-END COLLISION WARNING AND PROTECTION SYSTEM
Meaning, the vehicle stops automatically with sudden cross traffic/carts/other objects? or that is only available in S-class?

Thanks.

delete delete

No. code 253 pertains to the audible warnings and braking assist that comes when there is danger ahead. It includes preparing the cabin for impact (seat belt tensioner system), etc. along with providing brake assistance and modulation while you press down on the pedal hard. It will provide enough stopping power to bring your car to a halt without stopping so quickly that the car following you ends up in your trunk. You will get pedestrian warnings, but must apply the brake.

Sorry I didn't get it, during cross-traffic the vehicle will come to a stop?
I had two people who intentionally drove by while I was reversing from a parking lot and the vehicle didn't stop automatically.

As you mentioned, it won't stop when people walk but just audible sounds. Which is intermittent and turns out the COMAND needs to be replaced (hopefully under warranty which is another story yet to come)

Hi Raja, Does your datacard show these options on your car? These deal with pedestrian warnings and cross traffic specifically on the E Class.
We don't need you involved in any more fender benders. LOL

268 - EXPANDED BRAKE ASSIST (BAS+)
269 - BRAKE ASSIST PLUS CROSS TRAFFIC (BAS+Q)
271 - AUTONOMOUS BRAKE INTERVENTION/WARN. FOR PED. PROT.

:)
Yes they are available based on datamb.com
https://www.datamb.com/vin/1eQm3AV5yWW29GW6N

I believe that the rear-end collision system is actually referring to the long-range radar that scans for impending rear-end collisions. If you're about to be hit, the car will put on the brakes if you're stopped, and remove slack in the seatbelts, and prepare the cabin for impact. PRE-SAFE Brake, BAS Plus, Collision Prevention Assist Plus, and related systems will assist in forward collision events, including pedestrians, cross traffic, stopped vehicles, and moving vehicles, in certain conditions.

If you want the car to stop on its own in reverse due to cross traffic, that feature is only available in the W213 E-class and newer S-class. Just confirmed, unintentionally, that it works on my car but it works well!

While I'm here discussing the Datacard, sorry to hijack the thread:\
Does it mean, the trunk lid should close by holding the trunk key on the remote? It never worked to CLOSE. But worked fine for opening it.

Thanks.

To the best of my knowledge there is no long range radar in the trunk/rear area of our vehicles, Raja. There is radar in the side fenders for the blind spot assist, but that is it. The only long range radar is the Distronic star in the front grill.

I believe you can use the foot swipe, switches on the trunk lid, the switch on the driver's door, and the fob to close the trunk. I have never used the fob to close the trunk, and will have to try it tonight to see if it will close the trunk. I know all of the other ways work. How many ways do we need to close the trunk lid? :)

Holding the FOB key for trunk close works on both my 14 E350 and my wifes 17 GLE 350. All the other methods close the trunk too.

One of the things I love about Mercedes, the ergonomics of everything, literally every possible way you could intuitively think of to close and open the trunk, is available to you.

along with the keyfob, an app to start/stop and do these functions would be great. Okay, I'll stop day dreaming and save for future S-class.
Anyway, I just tested again and NO the Keyfob doesn't close the trunk.

Just being a bit too careful before my ELW ends July 2020. Oh boy, time flies super fast even with this slow E350. (Slowest of the bunch :).

Thats weird.... why does it work on my car and not work on yours?

Closing anything via remote always bring safety concerns and that is why MB makes dual-beam remotes, where window closing can be done only by close range.
You guys made me going to the garage and test trunk on my car.
The remote will not close it. The foot swing will close, starting with warning dong.
The door switch will close it, but you have to keep pushing it till full closure.

Yes Keith, they are in my datacard Dan sent long back.