Please help! Parking sensors falsely alert.
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Please help! Parking sensors falsely alert.
2020 GLC300 4matic, 30K miles, with all-round sensors/cameras (I forget the marketing name for this system).
Very often when driving in the city, the system alerts for the entire side of the car, or the entire perimiter (indicated as a red border around the graphic of the car), for no apparent reason.
Well, it seems to be when there is metal with about 3 feet of the car, for example a tram track on the left or right, a metal utilty box or street pole, or even another car. But 95% of the time, it does not happen in these situations.
This happens even when steering wheel is straight and the car trajectory is parallel to the metal object. Most often it's when stopped in traffic, with the car remaining in Drive and the foot on the brake/pulling off after stopping.
The car is regularly and carefully cleaned. This was not an issue the first couple of years, but not sure when it started (at least a year or two ago).
Dealer said there was no explanation (while it was under warranty).
Otherwise, the system performs as expected when parking etc.
Very often when driving in the city, the system alerts for the entire side of the car, or the entire perimiter (indicated as a red border around the graphic of the car), for no apparent reason.
Well, it seems to be when there is metal with about 3 feet of the car, for example a tram track on the left or right, a metal utilty box or street pole, or even another car. But 95% of the time, it does not happen in these situations.
This happens even when steering wheel is straight and the car trajectory is parallel to the metal object. Most often it's when stopped in traffic, with the car remaining in Drive and the foot on the brake/pulling off after stopping.
The car is regularly and carefully cleaned. This was not an issue the first couple of years, but not sure when it started (at least a year or two ago).
Dealer said there was no explanation (while it was under warranty).
Otherwise, the system performs as expected when parking etc.
Out Of Control!!
Joined: Nov 2018
Posts: 11,463
Likes: 5,354
From: San Francisco Bay Area
2019 C63CS
It's hard to say if what you are experiencing is normal or not. I have the same system in my 2019 C63S Coupe. Occasionally it goes off when stopping at a traffic light and the car next to me or behind me comes a bit too close, or I stop a bit too close to the car ahead of me. It doesn't detect metal, though. The sensors are ultrasonic. It however detects curbs at low speeds and warns about them, so that you don't accidently cut a corner and end up driving over a curb. Seems in some models they are more sensitive than in others at least judging from some of the reports, however I haven't really noticed any difference between my car and loaners etc. that I've driven.
Thread Starter
Newbie
Joined: Aug 2025
Posts: 4
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It's hard to say if what you are experiencing is normal or not. I have the same system in my 2019 C63S Coupe. Occasionally it goes off when stopping at a traffic light and the car next to me or behind me comes a bit too close, or I stop a bit too close to the car ahead of me. It doesn't detect metal, though. The sensors are ultrasonic. It however detects curbs at low speeds and warns about them, so that you don't accidently cut a corner and end up driving over a curb. Seems in some models they are more sensitive than in others at least judging from some of the reports, however I haven't really noticed any difference between my car and loaners etc. that I've driven.
Thread Starter
Newbie
Joined: Aug 2025
Posts: 4
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