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Unlocking from inside unreliable (2025 CLA)

GrandPursuit

New Member
Joined
May 18, 2025
Messages
10
Location
UK
Car
CLA
When exiting the vehicle occasionally only the driver's door unlocks, and this can cause the alarm to go if if kids are in the back due to the internal sensors and the car being "locked".

So the process is go for a drive, stop somewhere... The car is in D and HOLD is enabled.

Turn the car off... this successfully puts the car in P and the handbrake engages, engine turns off.

Try opening the boot... locked. Try opening a rear door from the outside... locked. Cue car alarm going off due to e.g. my daughter being in the car.

This only happens every now and again but is annoying when it does. Any fixes, a known issue, or will the car have to go to my friendly neighbourhood Mercedes dealer?
 
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When exiting the vehicle occasionally only the drivers door unlocks, and this can cause the alarm to go if if kids are in the back due to the internal sensors and the car being "locked".

So the process is go for a drive, stop somewhere... The car is in D and HOLD is enabled.

Turn the car off... this successfully puts the car in P and the handbrake engages, engine turns off.

Try opening the boot... locked. Try opening a rear door from the outside... locked. Cue car alarm going off due to e.g. my daughter being in the car.

This only happens every now and again but is annoying when it does. Any fixes, a known issue, or will the car have to go to my friendly neighbourhood Mercedes dealer?
Welcomes to the forum!

It is a new car.

I would strongly advise taking it back to the dealer. Any attempt to fix it yourself could invalidate part of the warranty.
 
Welcomes to the forum!

It is a new car.

I would strongly advise taking it back to the dealer. Any attempt to fix it yourself could invalidate part of the warranty.
Thank you. Of course I wouldn't attempt to fix it myself, but I was just checking before I phone Mercedes whether there are any known "tricks" with this which come about on forums.

e.g. press and hold the lock button to give the central locking system a reset... that kinda thing.
 
Thank you. Of course I wouldn't attempt to "fix" it myself, but I was just checking before I phone Mercedes whether there are any known "tricks" with this which come about on forums.

e.g. press and hold the lock button to give the central locking system a reset... that kinda thing.
Have you tried pressing the unlock button on the key twice?

There is often a default locking mode whereby when you unlock only the drivers door unlocks, pressing the key unlock button a second time will open all doors.

These features are user programmable from the setup menu on the scr
screen 👌👍

It would be worth looking at the manual to see if there are any descriptions of the locking options.
 
I usually use the Android app to unlock the car... my wife would use her key.

All the doors open with both, as our daughter can get in fine and we can also open the boot.

The thing is this is sporadic - sometimes we pull up and then all doors will unlock with the driver's door opening from inside, other times it's just the driver's door.

I checked the options and had a look at the manual. As you say, probably a dealer job, something doesn't seem quite right.
 
Have you tried pressing the unlock button on the key twice?

Interestingly I just forced myself to manually check the keys, despite me thinking both were on "unlock all doors" setting.

My wife's was on "unlock driver door only" and mine was on "unlock all doors".

However, the unlock from inside thing where it was only unlocking the driver door only seemed to happen to me. I wonder if this is a bug if both keys are on different settings? I tend to use the phone app to lock/unlock anyway since that way I can have the key buried at the bottom of my pocket, and my phone is always handy anyway. I checked settings on the car also, but no options for unlocking. We use a separate profile each with our own favourite radio stations, etc, set.

Anyway, setting now changed. We have booked it into Merc next week.
 
I've no idea if this is of interest to anyone, but I've done some experimentation and if you unlock the car when "unlock driver door only" is set on the key, only the driver's door unlocks after a drive too.

So without boring you too much, I think the car was getting confused on how the car was unlocked since my key and my wife's key were on different settings, and I use the app to unlock the car. TLDR; As we want all doors to be unlocked anyway when unlocking (who doesn't??), I have set both keys to do this now. So hopefully the software bug shouldn't just unlock my door when I have driven after initially opening the doors with the Android app.
 

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