I have the craziest problem that so far the dealership has done nothing to solve the problem. It is now in the shop for 3rd time and supposedly **Mercedes** is there now overseeing our complaint while they attempt to make a repair. This happens intermittently but I would say it happens 4-6 times per week every week for the past 3 months. I have owned the car for 6 months. I drive somewhere, lock the car (my mirrors are programmed to fold in) and when I return to the car 20 minutes later, 40 minutes later, 2 hours later, etc. the drivers door lock button is in the UP position. I usually lock the car by pressing the button on the drivers door handle but sometimes I lock it on the passenger side if my wife is driving and I have the keys in my pocket. Sometimes when we get back to the car all 4 knobs for all 4 doors are in the UP position. The mirrors are always still folded in and the alarm is always still set. If someone opens an unlocked door the alarm goes off. If I go to open the door with the keys in my pocket, then the door just opens and no alarm, (which makes sense). This occurrence has occurred during all weather conditions, at grocery stores, health clubs, private people's driveways, and usually there are no other similar cars like mine in the area. The dealer cannot duplicate the problem when they hook up a computer to the car sitting in their lot. For that matter, it has never happened in my own garage. It has happened dozens and dozens of times, outside at all diffrent times of days, locations, time periods, etc. The dealer has told me that they cannot simply change the locking module(s) or computer unless they can replicate the problem because Mercedes wont approve work like that unless they are sure it will fix the problem or can see from the computer that a specific part is malfunctioning. In the meantime I have ben driving crappy loaners and they havent fixed the car yet.

 

Try to be patient, problems like this while rare are exceedingly difficult to diagnose. Looks to me like the dealer is trying to cooperate but from their standpoint its impossible to repair a problem that they can't see or duplicate.

 

be patient...in the meantime, ask them for a comparable loaner car? At our local dealer, they have GLK's, C's, E's, ML's, R's, even an SLK...so if you're persistant enough, the adviser could hook a brother up, no?

 

I had the same problem (and more!). The problem was finally tracked down (after 5 service appointments!) to a dead cell in the battery. An insufficient voltage caused the door lock computer node to malfunction.

 

It took us 5 times in service as well to finally fix the problem. Of course I had to get Mercedes involved because the dealer kept telling us they were changing parts, but we caught them lieing to us. They really didnt replace anything the 1st 4 visits. They couldnt replicate the problem when they had it hooked up to the computer. They just couldnt find the problem so they could not justify changing parts. They did fix it with permission from Mercedes. They changed a bad control unit for the central locking system and they replaced the latch and lock assembly, and the door control module. The car was in the shop for a total of 29 days. They did reimburse us for our trouble. They offered me $700 (my monthly payment), or a free accessory, so I got the running boards installed (a $1200 value). They did the right thing but it sure was a nightmare getting the problem to stop which it has!!!

 

Thank goodness its fixed, I was waiting for the results as I followed your thread as I to have a 09 ML350....at least you got the running boards, I think it changes to whol look of the suv, I think it looks better, good for you!!