Spurious ESP and Brake Assist errors

[oldsteel]

New to this forum, I am a long term Merc Cabrio owner. I traded in my 2007 CLK with 150K miles on it for a 2018 220D cabrio with 17k miles last year. Now up to 32k miles its been largely good apart from voice controls not working at all which isn't a problem. A couple of months ago it started throwing up random 'Active Brake Assist function limited' messages, which wouldn't be a problem but it does affect driving such as varied gearchanges and poor acceleration. In for its first service at local main dealer I asked them to look at it. After some head scratching they announced it was fixed by 'software' - I suspect they loaded an update as I had to adjust a few settings when it came back. Needless to say it's not fixed, and the message still pops up randomly, but now I also get random ESP Inoperative messages as well. Having no faith in main dealer, alongside a minmum 4 week wait to book it in, I approached a local Mercedes Indy to look at it (just a few days wait). It turns out the actual fault was 'Implausible data received from control unit ...' He supplied me with the printouts from Xentry and basically said there is nothing he can do and it might be due to CANBUS(?) errors - essentially poor connections in the wiring loom which can be affected by water ingress. This started me thinking that these errors only pop up when the weather is bad, so could be due to water? Has anyone else had this and any suggestions? I am thinking it might only affect the cabrios - I see some posts about reseating the ABS sensor connectors - is this worth doing? I might invest in an error reader so I can do one reseat at a time and and check the results. Any ideas gratefully received.

 

[DSK]

There’s been a few threads on here lately including myself, of water ingress.

Issues can stem from inefficient/blocked drains, to sills filling up with water and that not draining out, plus more.

Lovely modern engineering. If I asked school kids to design me a car, they’d do better than the half wits in industry today!


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[sl500amgsport]

I occasionally get the Brake assist fault appear in bad weather, it does not effect performance at all. I queried it at Mercedes dealership and they told me it is a common known issue in bad weather on many models as the sensors get dirty...

Out of interest, has your car had the recall work done for the wiring loom? This is work under the car where the wiring loom is pulled too tight which could lead to wire exposure to moisture, the wiring is supposed to have additional support brackets added removing the pressure?

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[oldsteel]

Thanks @DSK will check out the drains! I have cleaned all the sensors many times, behind RV mirror and down on the bumper, so ruled that out as a cause. I might expect that if it was a sensor it might generate a more meaningful error message? How do I check if the recall work has been done? I am the second owner of this car.

 

[sl500amgsport]

You can call any Mercedes garage and give them your reg & vin and they will check for you or yourself online at:-

Current recalls | Mercedes-Benz

Find out about the latest recalls and see if your Mercedes-Benz is affected.

www.mercedes-benz.co.uk

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[sl500amgsport]

If it hasn't been done could be the cause...

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[oldsteel]

Thanks for the info - I checked and that recall didn't affect my model.