Growling noise from the bottom? when opening the door
 

So it's not the first time that i'm hearing this noise when I come up to my car in my garage in the morning.
Typically, I unlocked the car without pressing button on my key fob but I just grab my door.

When it's unlocked, it makes the beeping sound and that's it.
But, once I open one of two doors, it makes some sort of growling noise. I feel like it's from the bottom area but I might have mistaken where it was coming from.
It makes the noise for about 2 seconds or 3 seconds when it goes longer (this morning).

I felt the noise for several times during the last few weeks. But, it is really worrying that it got that louder.
I tried to capture it in a video but I don't have the sleight of hands skill.

Do I have to worry about the ABC pump going out?
I don't have any other issue going on than:
1. Idler pulley making some high pitch noise, which I was going to take care of later when it gets louder.
2. My seat lumbar support loses air but it gets pumped up automatically. (Happens quiet frequently but I don't know where to check yet. (need more research))

Can anyone give me some advise where to look at? or anyone have gone through some similar issues?

First of all, welcome to the forum! Please take a moment to visit the User Control Panel and update your profile to include your car's model year, and your location (at least country). This information will then appear below your name and avatar on the left side panel next to each post you make. This will greatly help others to give you better information. If you are using the mobile version of the site, you will need to switch to the "full" version to get to the User Control Panel.

My guess is that it's the Sensatronic Brake Control (SBC) pump pressurizing the brake fluid. When you open the door, the CAN bus wakes up and the vehicle goes through various checks, one of which is for proper brake fluid pressure. This is perfectly normal. In fact, if you are in the USA< your SBC system now has a 25 year, unlimited mile, unlimited owner, warranty. Note that this has nothing to do with ABC, as that only operates with the engine running, and unfortunately, has no extended warranty.

Thank you! I just updated my profile following your advise!
My W212 E350 makes that growling sound when I first accelerate the car at 20mph ish. The noise&vibration were coming from the passenger side front area. Dealer said that it's checking out the braking system.
My 2016 bmw X6 50i makes the similar noise when I unlock the car. But was not this loud as my SL makes. Thus, I was worrying that something might have gone wrong :)

I hope that it's brake checking like you said! I have a couple of question to ask!
1. Do you have any idea for tick noise and a little impact from the gear know when I brake the car to shift the gear from P to D or R? I'm not sure it's supposed to make the tick as it's unlocking the shift knob so that I can change the gear.
2. When my seat lumbar support loses some air and keep inflates itself, where do you suggest that I should look into for the repair?

Thank you Rodney in advance!!

1. I believe what you are hearing is an electronic lock on the shifter being released when you press the brake pedal. It will make a small sound as it releases the pawl, but it should not be very loud. There is a not uncommon problem with that pawl breaking, so if the noise is loud, it might be a symptom of impending failure. Search the forum for "cant shift from park" for all the details on the failure and repair.

2. You have a small leak in the seat pneumatic system. Mine does this too, maybe once every 20 minutes. I would not worry about it unless it fails totally.

Hi Rodney!

Thank you so much for sharing the information. I have tried to capture the moment in my video and to duplicate those issues.
I uploaded few videos on Youtube so that I can present them to you.

Loud(I think) SBC noise. It happens on the road during the ride as well.

• You Tube
• You Tube

Gear Shift Tick noise when brake is engaged. Shifting works okay at the moment.

• You Tube

As far as the PSE goes, it keeps running on my door locking mechanism as well. I feel like it's every 5 mins or less. I actually experienced battery drain a month ago and replaced both batteries, which costed me $500 each at my dealership. Do you think that I should go try to fix the leak? I'm planning to get an extended warranty but am not sure how much this repair would cost me as I'm trying to do some math with $250 deductible + excessive warranty price vs paying out of my pocket.

Thank you so much! I'm learning A LOT throughout this.

Both of those noises are normal. All R230's make them. As for the PSE pump running, About the only thing that causes it to cycle when the engine is off is a defective trunk latch. See the sticky at the top of the forum page for info on fixing that.

Oh I felt that it was too loud for it to run that loud in every 6th brakes. But, that's a relief!
Thanks again for checking it out :)
I paid my attention to my PSE pump and it seems like it doesn't run when the engine is off but only when it's running. Is it related to the defective trunk latch although?

If the trunk latch is broken, it can cause the PSE pump to run periodically with the engine on or off. If it runs continuously with the engine on, it may be a multi-contour seat leak.

Amazing, this! Literally experienced the same issue just this past weekend, twice, but I've been unable to reproduce it since.

Upon opening the drivers door I hear various clicks and whirs, but then twice was a loud growling from what I imagine is a pump. To me the sound appeared to be coming from under the hood on the passenger side, but it may have been sound bouncing off of the garage wall on that side.

I also tried to capture it on video! No luck.

As Rodney mentioned there may be a leak in the air supply to the bladders in the seats. I've never seen an R230 that did not have this problem. It is discussed in detail here: https://www.benzworld.org/forums/r23...-controls.html.

Since I couldn't care less about a simple lumbar adjustment, to protect the pump from wearing out prematurely on my car I changed the coding for the PSE pump to disable air supply to the seats using Star Diagnosis.

As I explained, that's the perfectly normal sound of the SBC (Sensatronic Brake Control) pump pressurizing the brake fluid. Each time the car "wakes up", it goes through various checks and if the brake fluid pressure is oo low, it operates the pump. Opening the door or trunk will "wake up" the car. You may also hear some small thuds or thunks from the brakes themselves as SBC also calibrates the system to set the proper distance of the pads from the rotors.

Oh no, I;d have to fix mine! I have the multi-contour seats and often use the "pulse" feature when my back is tired. I especially like it on long drives as its randomness helps keep me alert.

@mb_hayden
Are any corners of your car dipping when sitting over night?

I just found my right front unusually low.

I've found in the half a year I've owned my car that if I stressed everytime this thing made a weird noise or had a slight vibration, I'd go crazy tracking down absolutely nothing. Between the wife and I, we've put about 12k on the car in six months. It's fun as hell to drive.

Hi Sean!

Sorry that I wasn't able to come back to here. My life got super busy for the few weeks.

I don't particularly see my suspension to get lower in one direction. I might have not noticed so I will keep checking on that.

I think that since the air leaking, my car makes some air leaking noise? when I ride on highway and go through a smooth bump (up and down road)

I am planning to visit a dealer in a couple of weeks or so to check on these.

My SBC keep checking itself (making growling noise) in every 3 brakes. I hope they have a way to make it quieter or maybe extend the cycle.

Thank You!
 

Thank you for this thread. I'm a new member to MBWorld. The wife and I just bought a 2007 MB SL550, 50th Anniversary Edition, with 30,600 miles. We've been looking at convertibles for several years and finally "pulled the trigger." We're loving this car, so far. I was concerned when I heard the noise from underneath when I opened the door after it sat for a day or so. Glad it's normal as the brake system pressurizes. I'm sure I'll be back with more questions and hope I can find answers from you folks that have experience. This is our first MB. We're looking forward to some open air driving this spring and summer on the pretty days here in Arkansas.
https://cimg0.ibsrv.net/gimg/www.mbw...f44ff255c.jpeg
2007 SL550 50th Anniversary Edition
https://cimg7.ibsrv.net/gimg/www.mbw...3b438cec4.jpeg
2007 SL550 50th Anniversary Edition
https://cimg5.ibsrv.net/gimg/www.mbw...7ea86d5d7.jpeg
2007 SL550 50th Anniversary Edition
https://cimg3.ibsrv.net/gimg/www.mbw...576a37b41.jpeg
2007 SL550 50th Anniversary Edition
https://cimg1.ibsrv.net/gimg/www.mbw...8a533495e.jpeg
2007 SL550 50th Anniversary Edition