Hello, Ihave a 1999 S500 and recently encountered this problem. For some reason all my doors and trunk will not automatically (keep from slamming)closes for me. I would have to slam the door/trunk to keep it close. To be honest I have no idea what this part is call.Any suggestion or adviseon how to get this fix isgreatly appreciated.

Thank You.

 

Is it just the doors and the trunk? What about the central locking, is it acting wierd, or is it operating as it should?

Two things that I could think of, depending on your response. 1) the pump that controls your soft-closing is in the trunk area above the left wheel-well. 2) the pump which controls central-locking, referred to as the PSE Pump, is located on the right side underneath the back seat, and sits in rubber foam box.

If it's just your doors and trunk, I'd look at item No. 1

If it's your trunk and central-locking, I'd strongly look at No.2

When I have to replace my PSE Pump, it was because I had no Central-locking, and I had to slam the trunk and the handle would not retract.

Hope this helps

 

there is a fuse for the closing assist pump in the trunk fuse box.. you can pull the fuse and then plug it back in and it should start to work again temporarly. it will stop working again because there could be an air leak in the system which causes the pump to continuously run which will cause the system to shut down.

 

the central door locks fine....its just the door and trunk that won't soft close. I will troubleshoot this problem. Thank you very much.

 

Thus far, I've not had an issue with the soft-close, accept for when it got really cold here, then the passenger front door would not draw in. But when it warmed up it seemed to work just fine. So, I haven't bothered it since. But when my PSE Pump started malfunctioning, I experienced a range of other things,i.e., the remote would unlock, but would not lock the doors, sometimes the locks would activate by themselves, the trunk had to be slammed in order to close it, the trunk handle would not withdraw unless I slid the little lever inside the trunk lid and then slam it! I had a mechanic to troubleshoot it, and he removed the fuse for about 30 seconds which didn't help at all. Finally, he came to same conclusion that contradiction his earlier admission, that it's the PSE Pump.

This is what I suggested may have been the problem when I approached the mechanic initially, based upon information I received from this forum, but he initially said, "Nooo," "If it was your PSE Pump, you would know." Well, duhhh! I replaced the PSE Pump, and everything worked as if there had never been a problem.

But I also remember receiving information via this forum regarding the same issue, that it may have been CAN issue as well. Well, CAN or not, I'll never know. Your issue "may not" be complicated at all. It "may" simply be an issue of changing out the pump over the wheel well.

IMHO, sometimes, as a process of elimination, it's just best to change out the part that controls the function, and then see what goes from there. Sometimes, trying to diagnose a certain thing can be more time consuming, with the findings being inconclusive. If there is a bind in the lines, if you replace the pump and it still acts the same way then atleast you'll know that it wasn't the pump, and then if you have the skill and the time, trace the vacuum lines. Just seems the simplest IMHO.

Good luck with that...let us know how it comes out.

 

Read the info on "closing assist" before replacing the $600 pump. It details an adjustment that has brought many pumps to life, and give you trouble shooting help,I was about to go for #3. Mercedes can not tweek yours due to liability issues, you can!
http://v12uberalles.com/

 

Thanks for the info Peter! That has helped me a great deal, and good information to keep around too! Good look'n out.

 

I had issues with this also, did the pull fuse bit, it would work for a few times. I also found out you can adjust this screw 1-3 turns and it will fix the problem. I had my mechanic do it when he was switching my 300sd 93 140 over to run on veggie and now ALL the doors & Trunk work great! Granted its only been a week, I've had no issues. I've also read where people have done that and its worked for 1 year +. Sure beats spending 600 on some pump.

If you've got the patience to take out the back trunk liners then its not too difficult. My mechanic did it for basically free since he already had everything out for the greasecar conversion. btw the car runs amazingly quite while on grease!

So try the close assist search. or try this link which is pretty great with pics. I know somewhere else though it talks about the screw with pics. Basically you take the black housing off (careful with the red lines that go to each door & trunk as they can break) and back this screw out so it hits this sensor after 3-4 seconds b/c after 2 10 second attempts it times out.

Patience I am learning is a great thing with the 140 because I sure love mine & pays off!

 

A link to the whole site great info on many things
http://v12uberalles.com/