ElastomerGuy

I've got a 2019 S65 AMG. I bought it used in July, 2023 with about 7.5k on it and it's got about 14k miles on it right now. I really like the car but in the past month, it has unexpectedly applied emergency braking for no apparent reason. The first time was at about 75 mph with someone following me closely as I passed a vehicle. Other than the vehicle beside me that was being passed, there was nothing else in the road. That was scary and I'm sure the person following was just as upset with the whole thing as I was. It happened again yesterday. The road was clear this time with no one around. I was going about 45 and for no reason, it did an emergency brake. I have no idea what is causing this but it's pretty unnerving and I'd like to prevent it from happening again. Anyone else experienced this? Any suggestions on what I can do to prevent it from happening again?
Thanks in advance for the assistance.

SW20S

Take it in and make sure that the sensors and the system are operating properly

False alarms with these types of systems unfortunately do happen...I have had it happen on my previous Lexus and Chrysler vehicles.

ElastomerGuy

Steve:
Called the dealership today and asked them to look into it. We'll see what happens. Thanks for your input.
Ernie

as.thompson

This is apparently not confined to MBZ. I have a relative with a 2017 Cadillac Escalade that this has happened to several times and the dealership hasn't been able to find/fix what is causing it. Good Luck!

epnfrn

Sounds like my average 3-2 downshift! I’m sure they’ll be able to sort that for you - maybe have BenzNinja scan you as alternative.

carlosinseattle

I've had my car for almost 3 months now and it happened once, around 2 weeks ago. On my previous W222, which I had for around 11 months, it never happened. I've had this happen on other cars, caused by a dirty sensor.

BenzV12

My Mercedes-Benz also makes an audible loud warning (red triangle on the dash ) and it's about the collision system as well.My sensors are clean too. Well, I have not seen this in any W222 S Class either but as a preventative procedure you can turn it off albeit I would like to see it turned on

W205C43PFL

OP sorry to hear about this and I am glad you are fine. I hope it is just a software issue resolved through an update or dirty sensor that needs cleaning. There is another thread on this issue, if you want, you can also submit a NHTSA case: https://mbworld.org/forums/e-class-w...ke-assist.html

Barry Hanna

This kind of surprise can be unnerving, it happened to me and my wife said that I had come too close to a construction barrier on my right side. I’ve never had that intervention happen before. What has happened is the occasional sensor beeping for no apparent reason on every car I’ve owned since these systems arrived, but no active event.

In past years, some of my colleagues in the service department, M-B, would suggest cleaning the sensors with WD 40, then wipe with isopropyl alcohol to avoid false alarms. Certain coatings, waxes, etc. could, in their opinion, interfere with proper operation. These days, with the use of silicone based coatings, it’s more likely than ever that could be an issue for ultrasonic sensors. It’s worth a try.

Nice Ride

Is it LKA? Did you use your directional to pass? Just rulling out possibilities.

vinflouen

Phantom warnings and braking is a thing now.
my co worker has a tesla and same thing happens to him.
before i hit the highway, I disable mine.
very annoying and the computers cant drive better than i can.

W205C43PFL

Makes me worried of the future of autonomous vehicles, although those use LiDAR but still...

as.thompson

Why? What could possibly go wrong... go wrong... go wrong......

SW20S

In the era of distracted driving I think the safety value of this technology outweighs the risks.

CaliBenzDriver

Sorry to read about these close calls. Glad nothing bad has played out. You should have your MB specialist repair this ASAP before something goes seriously wrong.

Your front radar unit was not tuned properly. It's liw mileage and recent.... I don't think the performance of a fresh unit will be any different. Re-initialise this one and both of its side close-distance little radars.

It's very simple to deal with... chop-chop.

Eventually buy yourself a good scanner to prevent angry service clerks from feeding you amazing tales.

ElastomerGuy

Thanks to everyone who took the time to respond to my post. My car is scheduled for service next week to look into this, In the interim, I've turned off the collision detection. I would definitely like to have the technology looking over my back just in case I need it but with it malfunctioning as it seems to be now, I'll do without it for a bit. Again, thanks to everyone for their help and suggestions.

will_atl

Just throwing this out there, if you are using Cruise Control, and the car detects a speed limit change, it will brake down to the new speed limit (you can turn it off).

ElastomerGuy

Will:
Thanks for your response. Yes, I am aware that the car will slow down to the speed limit if I set it up to do that. I turned that off and the braking that I've experiences is violent, panic braking. The slowdown due to speed limit changes has always been gradual, as if one removed their foot from the throttle and just let the car coast to the new speed limit. At least that's been my experience. Again, thanks for your comment.

will_atl

Good luck at the dealership, I hope that they find the source of the problem

ElastomerGuy

Will:
Thanks. I don't have much faith in dealership service departments anymore since Covid. I think a lot of the truly capable techs have retired or are working in other fields. So, I'm hoping for the best but planning on just having to leave the collision detection turned off.

w126w221

I have had the same issue with my Distronic Plus on my 2013 S550, and they all use the same basic system which is an active radar front sensor, however they are more advanced with the W222s. The most important observations I have made when this occurs is that it appears to be triggered right as I am passing a vehicles blind spot, and they have blind spot detection. I believe the active rear blind spot monitoring radar present on the adjacent vehicle creates a phantom object that is "seen" by Distronic. I need to get my diagnostic setup back from a friend to recalibrate the front radar and see if that helps! Lastly, one positive aspect of Distronic Plus is it will always give you a few second warning before hard braking, which is enough to override the system by applying pressure to the accelerator pedal if your monitoring the system as intended.

MBNUT1

Fascinating hypothesis...

ElastomerGuy

W126W221;
Thanks for your input. That is an interesting hypothesis but it does not cover the most recent incidence of violent emergency braking that I experienced. This was on a two lane road with no other vehicle on the road beside me. There were houses along the road but no vehicles. And, I've travelled this road probably 10 times in the past year with no emergency braking experienced on any of my other trips. That being said, I appreciate your insight.

CaliBenzDriver

Everyone seems to agree, this is caused by the front center long-distance radar and not side radars or ESP Module itself twitching madly.


radar connector pins ....



radar leverages multiple MCU

It may or may not be the unit itself but its collateral environment upsetting the unit:

• Radar unit uses solderless circuit.
• Radar unit is poorly grounded.
• Radar harness connectors are not waterproof.
• Radar DC power supply is glitchy.

It's not built to work reliably so it does not. The dealer technician will tap in factory knowledge experts to quickly return your working car. Hopefully it all goes down well.


I used to get beep-beep ghosts radar warnings on a wheekly basis simply tied to a poor alternator voltage. Yet my radar scan always report disruptions but now works well.
✌️

carlosinseattle

Mine was caused by one of the side detectors. I saw the mirror warning light turn on when it happened in my car a few weeks ago. I was driving in the left lane, with a center left turn lane dividing the road. The only other car in the vicinity was a car approaching from the other direction, but it was at least 50 feet away and entering the left hand turn lane to make a left turn. The car never turned in front of me, but my hypothesis is that the MB safety systems was alerting me because of the other car's actions. Just FYI on my situation.