E-Class Coupe (C238) & Cabrio (A238) 2017 - E200, E220, E300, E350, E400, E450 [Coupes &Cabriolets]

2021 E450 coupe adaptive cruise control

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Old Oct 19, 2021 | 06:35 PM
  #1  
cpasam's Avatar
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From: Southeastern PA
E450C4 2021
2021 E450 coupe adaptive cruise control

This is a safety issue, so any help is appreciated:

This has occurred several times: while on a highway traveling 65 mph using adaptive cruise control, without warning the displayed highway speed limit suddenly changes from 65 to a much lower speed, and the car slows down. THIS IS NOT ACCEPTABLE AND DANGEROUS.

Is something set incorrectly?
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Old Oct 19, 2021 | 08:29 PM
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W205C43PFL's Avatar
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Originally Posted by cpasam
This is a safety issue, so any help is appreciated:

This has occurred several times: while on a highway traveling 65 mph using adaptive cruise control, without warning the displayed highway speed limit suddenly changes from 65 to a much lower speed, and the car slows down. THIS IS NOT ACCEPTABLE AND DANGEROUS.

Is something set incorrectly?
Normal, it is designed so the speed automatically adjusts to the new speed limit. I am hoping you can disable such "feature" though. Unless you are saying there are no changes to speed limit in real life and the car falsely read non-existence signs?
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Old Oct 19, 2021 | 09:22 PM
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2021 c300 Cab. Arrived 7/28/21 . 24 GLE 450e.
Originally Posted by W205C43PFL
Normal, it is designed so the speed automatically adjusts to the new speed limit. I am hoping you can disable such "feature" though. Unless you are saying there are no changes to speed limit in real life and the car falsely read non-existence signs?
Multimedia system:
Vehicle ,Assistance ,Traffic Sign Assist
That is the first thing I turned off. For heaven’s sake, read the manual. It’s fun to watch the speed limit sign change. Sometimes a ramp sign pops up, sign goes from 70 to 45. I knew even before I received the car that I was going to turn that off.
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Old Oct 20, 2021 | 10:58 AM
  #4  
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Originally Posted by Elvisfan0108
Multimedia system:
Vehicle ,Assistance ,Traffic Sign Assist

That is the first thing I turned off. For heaven’s sake, read the manual. It’s fun to watch the speed limit sign change. Sometimes a ramp sign pops up, sign goes from 70 to 45. I knew even before I received the car that I was going to turn that off.
Thanks for telling me this : )
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Old Oct 20, 2021 | 02:54 PM
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W140
Clip

Could you upload any clip related from your car?
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Old Oct 20, 2021 | 03:49 PM
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2017 mercedes GLE 43 coupe
Traffic Sign Assist p.194 of owners manual

Warning when the maximum permissible speed is exceeded
The system can warn you if you unintentionally exceed the maximum permissible speed. To do this, you can specify in the multimedia system by how much the maximum permissible speed can be exceeded before a warning is issued. You can specify whether the warning is to be just a visual warning or an acoustic one as well.

This is what was in the back of my mind when I earlier thought you could prevent car from decelerating as pass a speed sign.
I don't think you can set the system up to drop to the speed limit...plus 5 or 10 mph as I previously thought.



Last edited by jester1; Oct 24, 2021 at 07:01 PM. Reason: wrong info.
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Old Oct 21, 2021 | 09:17 PM
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2021 c300 Cab. Arrived 7/28/21 . 24 GLE 450e.
Originally Posted by jester1
You change the settings so when you pass a speed-limit sign, it will slow to that speed PLUS an extra ex. 10mph.
I never thought about setting that up if possible, since I turned that all off. I adjust the speed. Not the car.
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