Sudden, abrupt braking
Thread Starter
Super Member
Joined: Jan 2016
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2023 S Class 2013 SL
Sudden, abrupt braking
‘23 223, abrupt slamming on of brakes, momentarily. 25mph in neighborhood, dry smooth roads, mid day. No squirrel, children, falling objects, nothing. Car never wrecked. Obviously quite startling. SA unable to replicate. Anyone else?
Super Member
Joined: Feb 2020
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From: Atlanta, Georgia, USA
2023 S580
This has been discussed in multiple threads in this and other forums. Has happened to me a couple of times in both of W223s. It'll scare the bejesus out of you when it happens. I'm not sure anyone ever found the smoking gun on why it happens though.
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From: Maryland
2024 S580
Unfortunately this just happens sometimes with these automatic braking systems. I have never had it happen in one of my MBs, but did have it happen in a Lexus and a Jeep. Something tricked the sensor and it thought there was something in your path.
Thread Starter
Super Member
Joined: Jan 2016
Posts: 512
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2023 S Class 2013 SL
I recall this being discussed earlier in other threads. But, I'm unable to retrieve them. I'm curious as to the question, if anything was ever determined with this error either by a dealer or by MB? I'd like to collect these episodes and present them to my SA as confirmation that I am not the only one experiencing this problem. Perhaps Wolfman can identify these other threads
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Joined: Feb 2020
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From: Atlanta, Georgia, USA
2023 S580
As I recall, the last thread was mentioning the poster was passing someone on a two-lane maybe, and the car braked unexpectedly - as I recall, it wasn't too long ago. You might scroll back through this forum to see if you can locate.
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From: Atlanta, Georgia, USA
2023 S580
I asked ChatGPT - here's its response:
Here’s what I found specifically from the MBWorld.org S-Class (W223) forums regarding posts about sudden or unexpected braking / brake behavior issues — including some owner discussions that closely relate to sudden braking or phantom braking events:
Some W223 owners have reported the car “suddenly braking” — often tied to the automated driver assistance systems like Distronic Plus (adaptive cruise / emergency braking) rather than a true mechanical failure: (MBWorld)
In travel/experience threads, multiple owners discuss how the adaptive cruise/braking systems on the W223 behave differently than on prior S-Class models: (MBWorld)
There are other threads (not always W223-specific but highly relevant) where people report cars slamming brakes without warning due to sensor/assist system issues — and these are referenced across MBWorld: (MBWorld)
🔹 Brake behavior is sometimes described as harsher or later than on older models, making automatic stops more noticeable and less smooth. (MBWorld)
🔹 Owners recommend checking settings or turning off certain assist features if the braking feels too abrupt or unwanted (though specifics vary by model and comfort level).
If you want, I can dig up direct links to the exact forum threads (with specific post numbers/URLs) so you can browse the user replies in full — just let me know!
Here’s what I found specifically from the MBWorld.org S-Class (W223) forums regarding posts about sudden or unexpected braking / brake behavior issues — including some owner discussions that closely relate to sudden braking or phantom braking events:
🚗 W223-Specific Topics on Sudden or Unexpected Braking
1. Phantom / unexpected braking complaints from ownersSome W223 owners have reported the car “suddenly braking” — often tied to the automated driver assistance systems like Distronic Plus (adaptive cruise / emergency braking) rather than a true mechanical failure: (MBWorld)
- In one long W223 review thread, an owner lists “phantom braking when Distronic is engaged — car will suddenly brake hard for NO REASON.” They describe this as a real concern and say they’re even considering legal action because of how abrupt and scary the braking can feel. (MBWorld)
In travel/experience threads, multiple owners discuss how the adaptive cruise/braking systems on the W223 behave differently than on prior S-Class models: (MBWorld)
- Several owners say the automatic braking tends to come on later and more harshly, and in some cases they prefer to disengage it entirely because it doesn’t feel smooth — which could feel like sudden braking to a driver who wasn’t expecting it. (MBWorld)
There are other threads (not always W223-specific but highly relevant) where people report cars slamming brakes without warning due to sensor/assist system issues — and these are referenced across MBWorld: (MBWorld)
- One experienced poster recounts multiple panic brake stops in different S-Class models (including some related to auto assist), happening on open roadways with no obvious obstacles — and dealers often say “system is operating as designed” despite owners finding it alarming. (MBWorld)
🧠 Common Themes from Owners
🔹 Phantom or false triggers from driver assistance systems — particularly Distronic and emergency braking — are cited as causing what feel like sudden braking events in some W223s. (MBWorld)🔹 Brake behavior is sometimes described as harsher or later than on older models, making automatic stops more noticeable and less smooth. (MBWorld)
🔹 Owners recommend checking settings or turning off certain assist features if the braking feels too abrupt or unwanted (though specifics vary by model and comfort level).
If you want, I can dig up direct links to the exact forum threads (with specific post numbers/URLs) so you can browse the user replies in full — just let me know!
Last edited by Mem30306; Jan 27, 2026 at 03:14 PM.
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Current/Last 5-years:GLS;G70;Alpina B8;X7;Accord. Sold:X7,TeslaS;S560;S550,X5;530e;L.Navigator;LS460
Had this occur in my GLS just couple weeks ago. I don’t remember it happening ever before other than once last year on the highway right before a bridge (which is understandable). But this recent one was in-town in dry, clear conditions, no traffic, no pedestrians, no tree shadows, around 35–45 mph and it did a brief phantom brake moment. I just ignored it and I don't care about it.
Probably not what you want to hear, but you are not going to be able to reliably track or fix it, unless Mercedes releases a meaningful software update (which of course they'll never do). They just rarely ever revisit issues that require R&D and fall under the category of less-than-perfect system.
The drive assist is still very safe and reliable to me. Tesla phantom braking used to be much more dangerous (and braking lasts longer dropping to seriously low speeds on highways) in the past. All fixed now last time I had a Tesla. I can understand it in a Tesla pure camera base, but don't see why Mbenz has this issue when they are using radar. Makes no sense. Never had this in any of my other cars/brands besides Tesla (no radar or LIDAR) and my GLS. Notably, neither of my W222 cars ever had this issue despite the nearly 100K miles combined in both cars.
Probably not what you want to hear, but you are not going to be able to reliably track or fix it, unless Mercedes releases a meaningful software update (which of course they'll never do). They just rarely ever revisit issues that require R&D and fall under the category of less-than-perfect system.
The drive assist is still very safe and reliable to me. Tesla phantom braking used to be much more dangerous (and braking lasts longer dropping to seriously low speeds on highways) in the past. All fixed now last time I had a Tesla. I can understand it in a Tesla pure camera base, but don't see why Mbenz has this issue when they are using radar. Makes no sense. Never had this in any of my other cars/brands besides Tesla (no radar or LIDAR) and my GLS. Notably, neither of my W222 cars ever had this issue despite the nearly 100K miles combined in both cars.
Last edited by S_W222; Jan 27, 2026 at 05:04 PM.
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2019 C63CS
All these systems have a certain percentage of false positives. That's just how it is. They are based on algorithms that occasionally mistake signals from the sensors as an obstacle when there isn't one. Nothing is perfect. All software has bugs. All you can hope for is that these systems get better with future generations. MB doesn't use LIDAR, other than for the Level 3 Drive Pilot that they just recently put on ice. The Active Brake Assist uses the cameras and radar sensors in the car. All it sometimes takes is the sun hitting the camera at an unfortunate angle causing a phantom image in combination with dirt on your windshield. Keep the windshield clean around the camera. Use a 50/50 water and alcohol solution to get the crime and streaks off.
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2023 E 450 Sedan. 2018 GLC 300. 2013 E 350 Coupe (retired)
Man destroys his Mercedes after it stopped abruptly in traffic wth his family on board. I believe this was in Japan or South Korea, in front of the dealership. Rumor has it he eventually got paid by Mercedes
Last edited by smiles201; Jan 27, 2026 at 06:51 PM.
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2019 SL450, 2019 E450 Luxury Trim Wagon, 2024 BMW I7 xDrive60
I had the issue once with my 2020 S560 and twice with my 2022 S580. Took the car into the dealer and was told “could not duplicate” and that “the system was operating as designed.” To be completely fair, it has also happened once in my current BMW I7.
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Man destroys his Mercedes after it stopped abruptly in traffic wth his family on board. I believe this was in Japan or South Korea, in front of the dealership. Rumor has it he eventually got paid by Mercedes
https://youtu.be/2xlEuCUvQIo?si=T3dLeEaKbZ4pU-lL
https://youtu.be/2xlEuCUvQIo?si=T3dLeEaKbZ4pU-lL
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