Diesel #2

Hey guys,

I have 2016 model which is equipped with the Collision Prevention Assist Plus PRE SAFE feature, when a speeding vehicle approaches from behind and gets too close (which happens a lot in L.A.) the vehicle brakes and tightens the seat belt quite harshly anticipating an impact. I do not enjoy this or need it none the less. When i disable this function, it restarts again when i turn the car back on. Is there a way to permanently disable this function without going to the dealer for it ?

Thanks

pamiboy

Can't help thinking, but next time I would consider doing a proper extended test drive and ask the sales person to demonstrate each and every feature. It's not possible on a regular test drive.

jahquan3

idk much about this feature but you say even when someone is coming up on you from behind it brakes? That makes no sense wouldn't that make the accident even worst? I can understand if you were approaching on another vehicle from behind.

pamiboy

BTW, I've seen a few stickers on cars that say..... If you can read this you are too close ......
The closer you come, the slower I go ..... .

The G Man

I don't think Mercedes or the dealer will permanently disable a safety feature, they will be liable if you get hurt in an accident.

mleskovar

+1 That's like brake checking which is arguably illegal.

KEY08

This is an indication that you clearly need to drive faster.

The G Man

He has a E250 diesel, clearly, he should be driving in the slow lane and not hypermiling in fast lane.

Diesel #2

Yeah i do not think they will either, but i will ask when i take it in to get the Finishing Touch application.

Oh and i never "hypermile", i did not buy a Diesel to drive in the slow lane or slow in general. There are other reasons why i purchased a Diesel besides just getting good MPG.

But i love how guys with 550s talk like they drive Ferraris, lol give me a break.

jahquan3

HA HA
I think they're just kidding around. I did agree that the feature seems silly if it's doing as you said it was. Good luck but as some one said you might just have to disable it each time you start up. It's kind of like the Eco Start/Stop item that many have debated over the need to perm disable.

KEY08

It's all in fun and yeah the 550 is far from a Supercar. I seriously hope you get this sorted out, because it sounds annoying as hell.

Diesel #2

Yeah ill give the dealer a call tomorrow and see if there is something they can do, it's not something that is happening constantly, the system kicked in twice so far. One time as i was approaching a vehicle and wanted to make a fairly quick lane change, i guess i got within the parameters of the sensors as i went to switch lanes and the vehicle braked hard from 60 mph to about 35mph.

cetialpha5

There are a lot of systems in the car and I think you may be confusing and combining a few of them. You are probably encountering pre-safe plus which tightens the seat belts if it detects an impending rear end collision. If the brakes are applied when the vehicle is stationary, it increases the pressure so it's not really brake checking a car. For the collision prevention assist, I can see it applying the brakes because you are closing too fast on the car in front of you. It's probably not use to people driving like maniacs, we call it cowboying around here when people switch lanes quickly to maneuver around traffic. It can get you a ticket if you do it too much around a cop. As others said, the dealer probably won't do it, but I bet it's probably in some Star Diagnostic system somewhere. You can buy a knock off system or get a system from members of this forum. They probably range anywhere from $350-$750 or more for a legit version.

mleskovar

"... when a speeding vehicle approaches from behind and gets too close (which happens a lot in L.A.) the vehicle brakes...." says to me he's not stopped.

I'll buy this one after his follow up posts............

cetialpha5

I think it's two separate systems and he is confusing the two or they both happened at the same time. If collision prevention assist plus is kicking in, it's kicking it because he's approaching the car in front too fast. So it brakes. However if in that same time, some other car is approaching from the rear quick, as in a typical chain reaction braking sequence, it's tightening up the seat belts because of pre-safe plus. It's not pre-safe plus tightening up seat belts and brake checking a guy. I bet if someone flew up on you without any traffic in front, it wouldn't apply any brakes, just tighten up the seat belts. So that's why I think he's confusing the two, two separate systems combined into one reaction.

pamiboy

Has anyone else experienced this problem?

400ixl

Which is pretty simple to resolve, pull out to overtake in good time in a safe manner and neither be initiated. However, having driven plenty in LA, LA drivers run in fear of someone actually getting in front of them, and drive up each others backsides all the time, causing the tailbacks they are thinking they are avoiding.

This means the people racing up your rear end is far more difficult to stop and they don't want to leave any sort of a safe distance.

Diesel #2

This might be a possibility. But its not a matter of confusing the two systems, rather that they both had to kick in at the same time. The reason i am thinking it was the vehicle approaching behind me that caused the braking, is because the one other time that Collision Prevention Assist kicked in, the vehicle only braked, it did not tighten the seat belt. But this time it braked and tightened the belt. I was not very close to the vehicle in front however, not very close for me and not very close for the computer is probably two different distances.

I will keep the system on for now and see if it happens again from an oncoming vehicle. But im amazed at how smart this vehicle is. Kudos to Mercedes for trickling down many technologies that are found in the S Class.

tresean1

Well, at least yours works...I cannot get my system to engage for the life of me.

raja777m

What happened? you can't get the system to engage when you're approaching a stationary object or if someone is approaching you quickly?

tresean1

it won't work in any situation

raja777m

oh, wow, that is bad. you have warranty, right? here is where the ELW gets paid off, lol. those sensors are around 1200-1500, based on what I read here on the forum.
I was as an intersection in traffic, used the hold feature, then when moving, I used the cruise control ( I was already less than 20mph), so, the distronic plus kicked in, and applied brakes, when the vehicle in front of me stopped.

Try at slower speeds, if it still doesn't work, make an appointment and take it to the dealer.