Key fob issues
Thread Starter
Newbie
Joined: May 2024
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w212 2010 E63
Key fob issues
When I shut my car off and try to lock it from outside it won’t lock. I have to turn the car back on and off again in order for it to lock. A few times the car has turned on but not let me shift into drive, I have to turn the car off and back on again. I’m assuming these two issues are related.
anyone else experience this?
anyone else experience this?
Super Member
Joined: Aug 2018
Posts: 697
Likes: 172
From: Seattle, WA
2019 M5 Comp, 2005 Ariel Atom 2
First easy thing to check would be your aux battery as they can cause all sorts of weird issues like this. Ideally check voltage w/ a multimeter, but the date code is stamped on the top once you remove the hold down and if it's pretty old I'd just start there.
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Joined: Jun 2004
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Are you tapping the handle to lock or using the keyfob to lock?
have you changed the battery in the keyfob?
are you using a start button to turn the vehicle on or did you pop it out and insert the key fob?
I like checking or outright replacing the aux battery as mentioned above and also check your main battery and replace the key fob battery outright - read the entire thread below on key fob batteries and improving battery connection inside the key fob.
turn the car on and off with the key fob inserted into the slot
the shifter is a know fail point as well and may need replacement.
but Occam's razor as it's applied to Mercedes-Benz indicates that there's one cause and that is most likely going to be the auxiliary battery and then secondarily could be associated with your main battery and then finally could be your key fob battery.
read through these, from the sticky:
Key fob issues
Shifter not shifting issues
The Sticky
have you changed the battery in the keyfob?
are you using a start button to turn the vehicle on or did you pop it out and insert the key fob?
I like checking or outright replacing the aux battery as mentioned above and also check your main battery and replace the key fob battery outright - read the entire thread below on key fob batteries and improving battery connection inside the key fob.
turn the car on and off with the key fob inserted into the slot
the shifter is a know fail point as well and may need replacement.
but Occam's razor as it's applied to Mercedes-Benz indicates that there's one cause and that is most likely going to be the auxiliary battery and then secondarily could be associated with your main battery and then finally could be your key fob battery.
read through these, from the sticky:
Key fob issues
Shifter not shifting issues
The Sticky
Last edited by PeterUbers; Jun 2, 2024 at 02:29 PM.
Thread Starter
Newbie
Joined: May 2024
Posts: 9
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w212 2010 E63
Thanks!
I’ll check the aux and then the main battery. I thought the fob battery might be the issue but when I went to get it changed the guy said the battery was fine. I think that main of aux battery might be the issue as I left on vacation for three weeks and when I returned I tried to start my car and the battery was dead.
I’ll check the aux and then the main battery. I thought the fob battery might be the issue but when I went to get it changed the guy said the battery was fine. I think that main of aux battery might be the issue as I left on vacation for three weeks and when I returned I tried to start my car and the battery was dead.
Out Of Control!!
Joined: Jun 2004
Posts: 13,799
Likes: 3,233
2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Thanks!
I’ll check the aux and then the main battery. I thought the fob battery might be the issue but when I went to get it changed the guy said the battery was fine. I think that main of aux battery might be the issue as I left on vacation for three weeks and when I returned I tried to start my car and the battery was dead.
I’ll check the aux and then the main battery. I thought the fob battery might be the issue but when I went to get it changed the guy said the battery was fine. I think that main of aux battery might be the issue as I left on vacation for three weeks and when I returned I tried to start my car and the battery was dead.
Out Of Control!!
Joined: Jun 2004
Posts: 13,799
Likes: 3,233
2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Thanks!
I’ll check the aux and then the main battery. I thought the fob battery might be the issue but when I went to get it changed the guy said the battery was fine. I think that main of aux battery might be the issue as I left on vacation for three weeks and when I returned I tried to start my car and the battery was dead.
I’ll check the aux and then the main battery. I thought the fob battery might be the issue but when I went to get it changed the guy said the battery was fine. I think that main of aux battery might be the issue as I left on vacation for three weeks and when I returned I tried to start my car and the battery was dead.
Super Member
Joined: Aug 2018
Posts: 697
Likes: 172
From: Seattle, WA
2019 M5 Comp, 2005 Ariel Atom 2
Yep, one visit for tinting my front windows took out my aux battery haha. Probably had to have the key on for some time moving them up and down. Although it was 8 years old according to the date code...
I've seen people say 'oh, you'll get a warning on the dash' - no, only sometimes. No warnings for me, finally noticed when my cruise control stopped working and I tested it at under 12v...
I've seen people say 'oh, you'll get a warning on the dash' - no, only sometimes. No warnings for me, finally noticed when my cruise control stopped working and I tested it at under 12v...
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Out Of Control!!
Joined: Jun 2004
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
And a battery tender does not also charge the aux battery - that only charges when the car is running.
some good advice from @CaliBenzDriver in this thread about dual battery tenders
https://mbworld.org/forums/e-class-w...tery-also.html
some good advice from @CaliBenzDriver in this thread about dual battery tenders
https://mbworld.org/forums/e-class-w...tery-also.html
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Out Of Control!!
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
keyfob nightmares
When I shut my car off and try to lock it from outside it won’t lock. I have to turn the car back on and off again in order for it to lock. A few times the car has turned on but not let me shift into drive, I have to turn the car off and back on again. I’m assuming these two issues are related.
anyone else experience this?
anyone else experience this?
you will want to scan your car to confirm a patern of CAN-B faults.
In these conditions your chassis is waiting for an excuse to DRAIN YOUR BATTERY kaput by disabling low-power sleeping modes.
This lack of supervision is so fleepin' low tech. A bunch of modules going banana endlessly.
Use your prefered scanner with code descriptions.
