Mercedes key not locking or unlocking sometimes issue
Thread Starter
Newbie
Joined: Aug 2024
Posts: 13
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Mercedes sl500
Mercedes key not locking or unlocking sometimes issue
Hi
i have a little issue with my ML 350 2011 w164. Problem is i have two key fobs and they seemed to have bad battery. I changed batteries on both keys and it worked fine for some time.
But now its not unlocking or locking, sometimes it works and sometimes not. I have to push many times and if im lucky it will lock or unlock.
no warning of bad key battery and car is fine, just the issue with the key not always working.
i also tried removing battery and put it back in and then it works fine for some days, then its hard to unlock and lock the car.
is there a resync for the keys? Or any ideas?
i have a little issue with my ML 350 2011 w164. Problem is i have two key fobs and they seemed to have bad battery. I changed batteries on both keys and it worked fine for some time.
But now its not unlocking or locking, sometimes it works and sometimes not. I have to push many times and if im lucky it will lock or unlock.
no warning of bad key battery and car is fine, just the issue with the key not always working.
i also tried removing battery and put it back in and then it works fine for some days, then its hard to unlock and lock the car.
is there a resync for the keys? Or any ideas?
Newbie
Joined: Jan 2025
Posts: 5
Likes: 0
ML320 CDI 2008
Had similar issues and could not work out until my whole rear SAM box lost other functions.
In the beginning I had to put my key next to the IR eye to open and I had turn the key in the ignition and take out, close the door and press lock.
One other issue I got the same time was the fuel gate, it went down from 3/4 tank to 1/4 in 20 minutes driving.
I haven't had more issues with locking and opening after changing the rear SAM box, only that it seems to recognition my car as left hand driven. Just only annoying.
I would say check the condition of your rear SAM box because these functions are in that SAM box.
take out the SAM box and open it carefully and inspect after water damage (corrosion)
this is common problem.
In the beginning I had to put my key next to the IR eye to open and I had turn the key in the ignition and take out, close the door and press lock.
One other issue I got the same time was the fuel gate, it went down from 3/4 tank to 1/4 in 20 minutes driving.
I haven't had more issues with locking and opening after changing the rear SAM box, only that it seems to recognition my car as left hand driven. Just only annoying.
I would say check the condition of your rear SAM box because these functions are in that SAM box.
take out the SAM box and open it carefully and inspect after water damage (corrosion)
this is common problem.
Newbie
Joined: Jan 2025
Posts: 5
Likes: 0
ML320 CDI 2008
It doesn't be so cold here but it was lots of rain and around 10 degrees celsius. mostly after it had rained during the night. Mostly in the early morning it didn't like to work eider did I ;-).
Last edited by Ake003; Jan 30, 2025 at 03:45 AM. Reason: spelling
MBWorld Fanatic!
Joined: Feb 2017
Posts: 2,316
Likes: 1,216
From: Baltimore County, MD
'13 s212 63 p30. '06 LX470
Have you looked into the alarm siren? If the batteries die within this module, locking and unlocking functions can be effected. Sometimes when you hit lock do the lights flash, but the car is not locked?
