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Driver assist program(s) fail

Old Dec 10, 2022 | 05:50 PM
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2020 GLC300 touring version (but I miss my '93 300SE W140 tank)
Driver assist program(s) fail

2020 GLC300W 25k miles: after 24-33 minutes using Driver Assist on local highways, I get a message in my DIC that "Active Brake Assist Functions Currently Limited See Owner's Manual". Often, I also get a message that "Active Steering Assist Currently Unavailable See Owners Manua." This has been going on for a month or so. The messages clear after 1 or 2 minutes and all becomes well again. Conditions are usually clear sky, 50-65F temperatures, steady 55-65 mph, zero traffic. My local dealer cleaned the lens of the Multi-function sensor, replaced the lens hood, and updated the programming, but it is still maltunctioning. I think the sensor is failing from heat build up (the 30-minute buildup time). I have checked www.mbusa.com and found 3 recalls have been performed on other things. I noticed that 2019 GLC coupes were recalled for Distronic issues producing the Brake Assist message.
Anyone seen this and knows what is wrong?

Last edited by edpare; Dec 11, 2022 at 01:18 PM. Reason: Spelling
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Old Dec 14, 2022 | 04:59 PM
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From the OP: there is a chip in the glass windshield exactly in front of the camera such that it cannot reliably focus on road conditions.
Technology met the real world and the real world won.
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Old Dec 14, 2022 | 09:12 PM
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I don't think braking uses camera, radars only.

What information does scanning return about goofy modules?

The fact it's reproducible and happens like clockwork is an interesting clue for diagnosis.

Last edited by CaliBenzDriver; Dec 14, 2022 at 11:57 PM. Reason: cam used to read street signs
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Old Dec 15, 2022 | 08:49 AM
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Originally Posted by CaliBenzDriver
I don't think braking uses camera, radars only.

What information does scanning return about goofy modules?

The fact it's reproducible and happens like clockwork is an interesting clue for diagnosis.

I don't know the verbiage but repeated tests resulted in "obstructed view".
Brake Assist also is used by lane keeping program which does not access Distronic.
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Old Dec 15, 2022 | 10:08 AM
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you're right about "Lane Assist" eyeing the road dividers through the stereoscopic cameras.
With a windshield impact obstructing the view, I can see the module calling it quit.
How big is your glass impact (pics) ?

Have you seen ads about fixing windshield impacts with a seringe and 3M glue kit... you may want to explore before replacing your windshield.
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Old Dec 15, 2022 | 10:44 AM
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Originally Posted by CaliBenzDriver
you're right about "Lane Assist" eyeing the road dividers through the stereoscopic cameras.
With a windshield impact obstructing the view, I can see the module calling it quit.
How big is your glass impact (pics) ?

Have you seen ads about fixing windshield impacts with a seringe and 3M glue kit... you may want to explore before replacing your windshield.
✌️

Repair shop sent his pix using GEICO proprietary software I can't access. The pix passed so it must be visibly damaged. Car will hopefully be repaired before I see it again.

Dealer will not accept a glue repair saying camera will still be obstructed.
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