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PSE Issues - Central Locks / Trunk / Rear Headrests / Soft Close

3K views 9 replies 3 participants last post by  Smokiesman 
#1 ·
Hello all - hoping you can help me through the next set of issues with my 2005 S500 4matic...

My central locking system, trunk release, rear seat headrests and soft-closing doors/trunk are all giving me issues. The buttons on the dashboard for the central locking, unlocking, and lowering of the rear headrests are inoperative, as is the trunk release on the driver's door. Also, the central locking system does NOT automatically lock when in drive and rolling forward, as the setting in the cluster calls for.

With the remote key fob, the "lock" button activates the alarm, but no longer actuates the locks themselves. If I manually lock all four doors, by pushing down the locks on front passenger and both rear doors, then locking the driver's door with the key, the "unlock" button on the key fob will actuates and unlock the front driver and passenger doors, but neither of the rear doors.

The trunk, which I believe should have a "close assist" is not working, and the "handle" - the air actuated polished stainless "tongue" - is stuck out, in the extended position. When any of the aforementioned items are called to be actuated, the PSE pump does run, I can hear it clearly. I do NOT hear any leaks anywhere. Last, none of the four self-closing doors are working either.

Earlier this week, things were functioning normally, locks were locking, trunk was popping, however the tongue was out and the self-closing doors nor trunk were not working. I had the interior detailed yesterday, and upon picking the car up, nothing worked. I assume they had the trunk and the doors all open for the 5 hours they had the car, and God only knows what else they did.

I did attempt to "reset" the system by removing the 20A yellow fuse, #62. This did not accomplish anything, nor did clearing the PSE system codes with my iCarSoft MB-II scanner/programmer.

I know the PSE has been covered extensively, however it is very difficult sifting through all the threads, and while so many seem hopeful, it then often seems the original posters has fallen off the face of the earth before answering the members!

Any help as always is greatly appreciated - I don't mind turning my indie repair shop loose on the car, but I always like having a little direction beforehand so as to cover my butt in the event of. I hate senselessly throwing parts at something and hoping for the best, as so many shops try to do.
 
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#3 ·
Yes, as I stated in the original post, I can clearly hear the PSE pump running when one of these switches is activated, and the front door locks will unlock with the key fob remote after having been locked manually. Furthermore, also as stated, I did "reset" the system by removing the 20A fuse, and clearing codes with my scanner/programmer.
 
#4 ·
When you lock if the vacuum system is all good, the pump should cut of within 4 seconds, if the pump runs for 17 seconds, you have a leak or diaphragm split. When the pump is allowed to run for the time out at 17 seconds it will not do it any good. Once fixed the boot handle will go back to normal.
 
#5 ·
I'll have to do a little more testing today, and time how long the pump runs when actuated - as I said, certain functions do not work at all, however, the remote key fob DOES unlock the two front doors, after they've been manually locked.

What is the best way to start chasing down a leak in such a complicated system? I feel as if I read somewhere the lines could be pulled off the pump one at a time to determine which component failed?

Thank you!
 
#8 ·
You may want to start with your trunk release ! These are a known problem for leakage. They develop cracks and will leak . You may want to pull the trunk liner out and get access to the pump and get better idea what it is doing. JMO but I think the motors in these pumps are kind of a weak link and are prone to burn up with extended run times . I had to go that route before I fig out problem. Hang in there nice to have a extra set of hands and ears when doing yer diagnosis . And if your pump is bad and if you have lift assist DO NOT BUY ANY EARLY PUMPS as they will not work with lift assist!

Smokie
 
#9 ·
Thanks Smokie - that's the general consensus, the trunk release being the culprit, or at least a good place to start. Good looking S500 you've got, the Sport package really makes the car. I'm planning to update/upgrade my '05 with the Sport appearance package and rims/tires. My 2007 S550, which I drive daily in Florida, is a Sport package car, black on black, and I love it. The S500 is my "winter" car for use in New Jersey/New York when I'm up here.
 
#10 ·
Thanks for the comments on my Starship! Those trunk releases are just plastic and I think that the slamming of the lid takes its toll and they crack out and that all it takes for a air leak and then the pump runs to much and that takes a dump ! Everything about these cars has to be working correctly or it is like a cascade of problems . Great when it all works but a nightmare when its not! Good luck with yours I hope you get it working again. I also watched a lot of Youtube videos on this and was very informative . My local indie finally bailed me out of my problem when he told me I had the wrong pump. He had a like new used one at the shop installed programmed and we had a working PSE system again! Money well spent to keep the rest of my hair !!

Smokie
 
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