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What makes doors on a W221 stay open by themselves no matter how far you open them. My 2013 S550 has an excellent feature when I open the doors on a slight incline they will hold themselves in the open position when I let go of them, however the driver door quit doing this after I got my car back from dealer today and now you let go of it and it closes by itself. Anyone know what the mechanism is that controls this? All other doors still work.
I've been searching both forums and google and nothing comes up.
There are cams on the door hinge bar that provide a passive resting point at a couple spots on most cars, including ours, so I'm not sure I follow. There's no way they can be damaged. At any rate, if it's a problem you've experienced post dealer visit, and not prior to, the obvious solution is to take it back to the dealer and complain.
I found out its called a Check Strap, a small shock absorber type thing like you'd find on the back window of a truck topper that holds it open. Same concept on the W221 that keeps the door from closing on you when parked on an incline. See below
Last edited by s550hollywood; 12-07-2022 at 11:46 PM.
Reason: Found proper name for part
In other words when you open a door on a 2013 S550 and you let go of that door, it stays in the position its in and does not move on its own. You have to put your hand back on it to either open it further or close it.
I found a video of how to remove the door panel, I'm still not sure as of yet where the check strap is located once I get the door panel off. I found out the thing that holds the door open is called a Check Strap
What makes doors on a W221 stay open by themselves no matter how far you open them. My 2013 S550 has an excellent feature when I open the doors on a slight incline they will hold themselves in the open position when I let go of them, however the driver door quit doing this after I got my car back from dealer today and now you let go of it and it closes by itself. Anyone know what the mechanism is that controls this? All other doors still work.
I've been searching both forums and google and nothing comes up.
I've been wondering about this with my car, and thought the issue was so esoteric that no one would even know what I was talking about. The doors from this era (2008 in my case) were supposed to have a feature that the door would 'hold' at any variable position. Mine no longer does, and just holds open more like a conventional door on any car at one or two points. Glad to see someone posted about this, and the part that may fix the problem (small as it may be). The question is....is the part still available? I've had numerous parts listed as available, only to find they are just kidding when I go to actually order.
Its a very nice feature of the W221 and helps to keep me from hitting cars beside me with the doors. It literally feels like it works on a vacuum motor but this is all I find on it. What I don't know yet is how easy it is to get to it once the door panel is off and why it failed while in for service. Looks to me like its behind the inner metal panel just behind the door panel trim. My wifes Mini Cooper doors have what I'd call stops where the doors will only hold in 3 different positions but not between those positions. When I open her doors, sometimes the car next to us is in-between those positions which means I have to hold her doors from hitting the car next to us or close it until it falls in the next position. Where my S class doors can be opened to any position and hold once you let go. Its hard to live without it once it fails.
Here's a video I found to help. He removes the door "check strap" and the video says its the same procedure 2006-2013 W221. The door Check Strap is the small shock absorber looking thing that holds the door open on an incline and this is how you would replace it. Cost at dealers of around $90-$100 for the part. Call your local dealer parts dept and ask for the door check strap for your VIN # to find the correct one for your car.
This is where its located once you have the door panel removed, I put a red square around it. Its held on with one bolt on the right side in the red square and then the other end is held on in the door jam when door is open. I liked to have never found any of this because I didn't know the mechanismn was called a Door Check Strap. Its a funny name because its not a strap at all, rather its like a small shock absorber like they put on a pick up truck topper back window door which holds it open.
Cool. I hadn't even looked at my door. Maybe I was confusing it with my W212, it doesn't have the shock the W221 has. I think... Anyway, glad you got it sorted and shared. I think I'll check mine now
the feature you mention about the door holds at any point in its arc - is it not an optional extra that comes with self closing doors ?
I believe this feature is mentioned in the manufacturer literature on all the cars. I'm excited to get this fixed on my car, again assuming the parts are still available--big if, as it would be a great feature. This is another thing I hadn't mentioned to the dealer, because I would have gotten a black disbelieving stare, and no one would have ever heard of such a thing. Now that I've got a part number I can proceed.
called a Door Check Strap. Its a funny name because its not a strap at all,
legacy name from horse drawn carriages - where it was once a leather strap that stopped it opening too much (so limits ... "checks" how far it moves) - industry standard usage
BOTUS- I knew there was some history behind it somehow. Hopefully this post will help people find what they're looking for because before I knew what it was called, I wasn't finding much from using the title of this post as my search term. This mechanism is just a small example that sets S Class apart from other cars. The German engineers recognized that sometimes cars are parked at different intervals from each other than other times so they created this to help us not hit the car next to us like some do.
Last edited by s550hollywood; 12-09-2022 at 10:34 AM.
I never ever seen any W221 with check trap faulty. It's very durable part so you need to check if there are any assembly issue.
I was wondering if it came loose or something because it was working the other day when I dropped it off at dealer and then when I picked up the car and got home I noticed it wasn't working and the door kept closing on me. However I would think if it came loose somehow, it would be sliding in and out of the door when I open it. Not sure as I haven't took the door panel off yet. I do know mechanisms like shock absorbers do wear out with time and the driver door gets the most use so I'm sure thats all it is.
I doubt your check trap hydraulic wear out, as I have told, this part is very durable and no way for 2013 car faulty. Just open door lining then you will see what goes wrong, just two bolts and less than 5min if you want to do inspection.
Correct, as S550 Hollywood says.
My 2013 has the same strap on all 4 doors and is a wonderful feature
Not only on inclines, but also crowded supermarket carparks....
I just replaced my door check strap which helps the door remain open on a slight incline or comes in handy when parking next to other cars and on windy days. It was the driver door check strap on a 2013 S550 / W221 and I can confirm all the instructions above are accurate for 2013 models. The door check strap was $80 at the dealership and took me less than an hour to replace it and put door panel back on..
Check Strap $80.32 Part Number 221-720-07-16
Last edited by s550hollywood; 12-17-2022 at 05:34 PM.
Reason: added picture of model
12-07-2022, 07:40 PM
