Hi everyone,

I'm hoping someone here might be able to help me diagnose a strange issue with my 2018 E63S (approx. 160,000 km). I'm hearing an unusual, intermittent beeping or chirping noise coming from the car. Here's a breakdown of the symptoms:

• I think the noise is coming from the engine bay.
• The noise is not present when the car is cold.
• Once the car warms up a bit, the beeping starts when braking.
• After driving a bit more, the noise continues even without braking, especially at low speeds.
• The frequency of the beeping does not change with speed.
• When the car is fully warm and comes to a stop, the beeping turns into a continuous tone, which stops right after when the engine is turned off.

I took the car to a local authorized Mercedes service center. They suspected it might be a foreign particle between the brake disc and pad, but after checking all corners, they couldn’t find anything wrong and returned the car without resolving the issue. They also did not check for any fault codes.

I connected Xentry myself and found two fault codes:

1. Air quality sensor has a malfunction. There is an internal electrical fault.
2. Actuation for engine mount has an electrical fault or an open circuit. There is a general signal fault.
   (This second one appears for both engine mounts A and B.)

The noise is quite annoying and definitely draws attention, so I’d really like to get it fixed. Has anyone experienced something similar or have any ideas what could be causing this?

Thanks in advance for any help or suggestions!

 

From your description, mileage and error codes, my hunch is that your dynamic engine mounts are shot and create a beeping/buzzing sound as they are trying to adjust.

 

The sound doesn't happen to sound like what is mentioned or highlighted in the video clip in this thread? heres the link
https://mbworld.org/forums/w213-amg/...hed-noise.html

 

Thanks. I think the sound is just like that. Were you able to find out if your car had that PCV issue?

 

I replied to the attached link thread and had the PCV issue, my car sounded the same and I had it fixed.
also 2018 E63S.

 

I started hearing the noise last weekend when driving to cars and coffee, parked the car and have not driven since.

 

@EilamS3 From my knowledge am I correct that the PCV system is the same as the oil separators? Are the oil separators what you had replaced/fixed to solve the issue? Can you post an invoice showing part numbers of what was replaced when you had that work done? Thank you

 

yes it is the oil separators, I hope this invoice helps I will say I got a crazy deal so it might be more…

 

Thank you for your response. You definitely got a crazy deal, I just got a quote for approx $4900 from a MB dealer.

 

Is this what you guys were hearing? Don’t mind my daughter talking in the background. It’s that faint beeping noise that I’m trying to figure out on my end

 

Yes that is what I was hearing in my car

 

Any particular error codes? I’m tuned so likely my CEL will never appear

 

I have no engine lights nor have I had a scan to see if anything is logged in the computer. I have not driven car since noticing the noise, I am quite certain its the oil vapor separators (PCV) causing it, as others have previously mentioned.

 

Sounds like I’ll be contacting my dealer again.

 

Goodluck, let us know what they say/happens