Mercedes Beeping Sound Continuous Unless Stopped

Muppetz · Dec 24, 2016

I bought my E350 used from a dealer 6 months ago, and since I bought it it's always made a very odd beeping noise after reversing onto my drive..

When it went in for a service 5 months ago I mentioed it, and they couldn't reproduce it, so I left it.

It's continued to do it, so when it was in yesterday for SOS inoperative fix I showed them a video of it happening and they still couldn't work out what is making the noise, nor could they reproduce it..

So - any ideas ?

I've uploaded a video here:

https://youtu.be/Iqu_M6SH-ZI

and another

https://youtu.be/kEqZ6JptNGY

Info:
Car is a premium night edition 2015 E350

It's not the parking sensors as the noise isn't audible in the car, and they aren't triggering (not close enough to anything)

I only really notice the noise when parking up at home, but then it's quiet enough at home to hear it. (our other car doesn't make the same noise, it's definately coming from the car !)

I've emptied the boot of all items to ensure it's not something of mine in the boot !

My route home from work is about 10 minutes, near home I go over several speed humps, and parking on my drive is a reverse down a slight incline.

Dealer says no faults on star

Anyone got any ideas what this mystery beeping is or how to further diagnose it ?

brucemillar · Dec 24, 2016

I could only start to guess. It does seem odd that it "only" happens on your drive and nowhere else.

Could it be that your drive has a some sort of gradient that is causing the rear suspension to self level and what you here is that leveling?

Does the car have some sort of tracker fitted by a previous owner?

The clue to me, would be in the fact that it only happens at home, on your drive, and not in a garage.(presumably with very level floor)?

If that is the case then it is something about your drive that triggers it I have absolutely no idea what could make that noise as it does sound like a noise that is intentional.

FIL, bought an A-class that had a Insurance tracker fitted by the previous owner. That made beeps at random. Have you any "unknown" leads hanging off the battery?

Deleted member 37751

Does your car have Airmatic? It could be the car finishing off the levelling process?

grober

First thing I would do is to nose in the car to your driveway when parking instead of reversing. That might eliminate a few possibilities?

jdrrco

A wild guess... As it's parked on a hill, could it be related to the anti-hijack thingy on the alarm? Perhaps try pressing the button with a crane symbol after you get out and see if it makes any difference.

wu56Shoozz

Good Guess there too Barney.. I was just going to say that..

jp 1

Just a shot in the dark, have you or a neighbour have a remote control garage door. Could it be sensor picking up..?.

richard

Put the parking brake on before you switch off car, wait 20 seconds, then see if it does it ?

I can hear my GLC parking brake go on as i get out. Now it doesn't make a beeping but it is something that operates as you get out of the car, and perhaps with the hill there is some sort of resonance happening ?

Richard

richard

My GLC did this today. Now I have to work out what it was. Gently parked (after 100 yard drive from a shed), and it was beeping just like that !!

R

paul_f

Sounds like a actuator being driven via PWM to me. With cold temps I'd guess the SCR system is purging the lines to prevent frost damage

MercE350

I have the same car and quite a steep drive, i drive in nose first, i have never heard a noise like that.

richard

Sounds like a actuator being driven via PWM to me. With cold temps I'd guess the SCR system is purging the lines to prevent frost damage

I'm pretty sure you are right. Theres a AdBlue metering valve and a delivery/extraction pump at the back of the car.

According to the documentation
a) the metering valve is PWM controlled. And can be run without float needle open to heat the valve.
b) The extraction pump takes the adblue back out of the pressure line into the container after circuit 15 (ignition) is turned off as part of the anti-freeze protection.
c) Adblue freezes at about -10C (and thus there is also a heating element)

Thank You Paul_F

Richard

Muppetz

Thanks for all the replies, I've not driven a lot over the last week, but have tried different things on each trip.... so..

drive or steepness of parking is not a factor, as it does it nose in first, or reverse in, or if I park on the road perpendicular to the drive, and indeed when I drove a short 5 minutes to the local DIY store this morning...

I looked for the anti-towing button but couldn't find it to try this ?

I see the suggestion it is something to do with adblue ? it's most definately a beep, not a pump or actuator noise though... ?

have tried opening the boot, the noise is no louder, it's definately something coming from underneath...

If it's a 3rd party tracker unit how do I check for this please ?

Thanks for the help so far !

Muppetz

Does your car have Airmatic? It could be the car finishing off the levelling process?

I don't think I do

First thing I would do is to nose in the car to your driveway when parking instead of reversing. That might eliminate a few possibilities?

tried this, nose in or reverse in, the same !

A wild guess... As it's parked on a hill, could it be related to the anti-hijack thingy on the alarm? Perhaps try pressing the button with a crane symbol after you get out and see if it makes any difference.

Only a very slight incline, but have proved it now in flat car park and flat road

Just a shot in the dark, have you or a neighbour have a remote control garage door. Could it be sensor picking up..?.

Now proved away from home

My GLC did this today. Now I have to work out what it was. Gently parked (after 100 yard drive from a shed), and it was beeping just like that !!
R

Thank goodness I'm not alone !

Muppetz

I'm pretty sure you are right. Theres a AdBlue metering valve and a delivery/extraction pump at the back of the car.
According to the documentation
a) the metering valve is PWM controlled. And can be run without float needle open to heat the valve.
b) The extraction pump takes the adblue back out of the pressure line into the container after circuit 15 (ignition) is turned off as part of the anti-freeze protection.
c) Adblue freezes at about -10C (and thus there is also a heating element)

Thank You Paul_F

Richard

definately a beeping and not an actuator noise though ?

Sambo

I've noticed this on a couple of my cars but never bothered to investigate.

I noticed it when reserving to park, then jumping out quick to go indoors - I didn't seem to notice any consistency with when it done it or why so just left it.

My 205 has a weird cricket typenoise behind the air vents in the dash that's currently bugging me. I've narrowed it down to when it's cold, but not frosty. Weird.

bellers

Anti tow is in the centre screen under vehicle settings as in s class. Mine makes a noise like a cricket chirping. I just presumed it's normal and walk away. Car will probably roll away one day.

paul_f

definately a beeping and not an actuator noise though ?

The noise in the videos above is a solenoid being driven via PWM.

You are hearing the frequency that the actuator is being driven at.

Muppetz

Brilliant, thanks for the help, dealer had no ideas !

Borrego Mingh1984

Mercedes Beeping Sound Continuous Unless Stopped

Mystery Beeping from the rear of my 2015 E350.... Any ideas ?

Deleted member 37751

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