W212 Alarm 'beeps'

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w212dcaf

Member
Joined
Jan 23, 2023
Messages
49
Location
Stratford-upon-Avon
Car
W212 E350 Bluetec AMG Night Edition Premium
Hi everybody,

I'm new to this forum as a member but have been reading posts and lurking for so long, I thought I'd join in, sadly with an issue I could use some help with - so not all that altruistic I'm afraid. Any help would be appreciated, I'll try and be as clear as I can in my wording below, but sometimes I don't know the correct Mercedes terms for some of these things. I'm fairly capable with a set of tools, but often time limited.

I have a W212 E350 Bluetec on a '65 (2015) plate, which recently saw the alarm going off silently (hazards flashing fairly fast) as soon as I pressed the lock button. I could then cancel the hazards by pressing the lock button a second time.

I have an AUTEL AP200 system for home DIYers, and it suggested LIN BUS 2 Faulty, as well as communication with the alarm siren. Understanding that this is likely the alarm siren causing both issues, I took the car to a Mercedes specialist who ran their STAR system over it and came to the same conclusion. They fitted a new alarm siren (£147 for the siren alone) and the silent alarm no longer happens when I lock the car. From the outside perspective, it seems to be normal and fixed.

However, I now get three tiny little beeps when I lock the car, and one when I unlock the car, that seem to sound as if they're coming from the front nearside area (opposite side to the siren I believe). It's driving me nuts, and I can't disable it. The 'acoustic warning' is switched off - the one that fires the horn when you lock it - so it's not that setting and definitely not the horn making the noise. I know it's tiny, but I'm a real nut-job for the details and it makes my inner Victor Meldrew grumble every time I lock/unlock the car.

In addition, if I press the button in the roof control panel (roof lining just behind the windscreen) to disable the interior motion sensor before I get out, it flashes red quite fast (compared with the slower flash I get from the button to disable tow away protection). However, not getting any fault codes on a complete system scan. Worth noting, when the alarm siren was faulty, pressing either button did not work at all (no LED on, off or flashing).

Has anybody got any experience with this or know what I need exactly to code the unit out to silence the dreaded beast? I'm reluctant to go back to the specialist as they scuffed my front bumper at some point over the two days they had it, and although only small, is enough to put me off going back. I won't mention their name as they were decent enough to say they'd fix it and didn't try to argue with me that it was their error, but as it's so small, the fear of them making more mess when fixing it with overspray or slightly unmatched paint is greater than the likelihood that it'll polish out to something only I'll ever notice. That and they're over an hour away, so requires a lot of messing about!!
 
Welcome to the forum.
I fitted a new alarm siren in my now sold W211 E55 and there was an option to silence the 3 beeps when locking the car.
Have you gone through the entire menu in the Convenience settings through the cluster to see if it can be turned off?
I've sold my W212 now so can't check for you myself.
 
Welcome to the forum.
I fitted a new alarm siren in my now sold W211 E55 and there was an option to silence the 3 beeps when locking the car.
Have you gone through the entire menu in the Convenience settings through the cluster to see if it can be turned off?
I've sold my W212 now so can't check for you myself.
Hi AMGeed, thanks for posting back to me.

Sadly I have. There’s an ‘acoustic’ notification which toggles the horn honk on locking but no other similar mention. I suppose I could try turning it on, locking, unlocking, and then off and hope the three beeps sync with the horn setting. Worth a try at least.
 
Hi AMGeed, thanks for posting back to me.

Sadly I have. There’s an ‘acoustic’ notification which toggles the horn honk on locking but no other similar mention. I suppose I could try turning it on, locking, unlocking, and then off and hope the three beeps sync with the horn setting. Worth a try at least.
It didn't do the trick. Turned acoustic sound (horn) on, locked the car, unlocked the car (beeps still there), turned the acoustic lock (horn) off, and the horn disables but the little beeps don't sync with it - they remain all beepy and smug.
 
It didn't do the trick. Turned acoustic sound (horn) on, locked the car, unlocked the car (beeps still there), turned the acoustic lock (horn) off, and the horn disables but the little beeps don't sync with it - they remain all beepy and smug.
It was worth a look. Sorry I can't assist further.
Does the user manual give any clues how to turn it off?
I'm sure it can be disabled by a Mercedes specialist with Star diagnostics if its really bothering you.
 
It was worth a look. Sorry I can't assist further.
Does the user manual give any clues how to turn it off?
I'm sure it can be disabled by a Mercedes specialist with Star diagnostics if it’s really bothering you.
Thanks anyway. I may have to face up to it and go back to the installers of said beep box.
 
The new sirens come coded to beep. It can be changed with star
I don’t suppose you know where exactly in STAR it can be done? I don’t think the place I’m going to know too much about the kit, so could do with going pre-armed with info.
 
Finally made a video for it. I'm hoping somebody doesn't say 'oh yeah, those beeps mean the expensive sensor thing is broken'... But on the off chance there's a simple solution...

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It did indeed need STAR. Alarm siren needed to be coded as a GB/U.K. siren, rather than the Euro spec as it comes out the box. Hardest part was finding the right option in the menu of star, but once the tech bloke found it, it was a few seconds to code, and job fixed. Nice and silent.
 
Recently fitted a new siren to my 211, actually quite happy with thee small beeps. Not too loud.
 

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