Ignition key wont even turn
Thread Starter
Junior Member
Joined: Sep 2019
Posts: 39
Likes: 5
From: Moscow
S-class W221
Ignition key wont even turn
I didnt drive my car all winter, its spring now and all of the electronics are off, i could barely even open the car door, when i got inside to start the car, but the key didnt even turn, everything was stiff, the steering locked, when i put the key in the ignition, nothing light up, I dont know if this has ever happened to anyone else, I dont know which battery is dead, the one in the boot or the one at the engine bay area.
Please advise
Please advise
MBWorld Fanatic!
Joined: Jun 2021
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From: Fleriduh
W212 E63S Wagon - GSL580 - E63 - E350 - C300
You need to charge your batteries. The first suspect (for the key) is the smaller aux battery. For giggles - you can hook some jumper cables to another (running) car and see if the voltage enables the key. If you can then start the car - maybe just maybe the alternator will charge the system up.
MBWorld Fanatic!
Joined: Oct 2019
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From: Colorado
G550
When you store your car for any prolonged period, you need to connect a battery maintainer to it. Don't believe the willie-nillies who insist you'll overcharge your battery and destroy it. Likely you've destroyed your batteries by sucking every last electron out of them.
Super Member
Joined: Oct 2023
Posts: 543
Likes: 191
W221 S500
I didnt drive my car all winter, its spring now and all of the electronics are off, i could barely even open the car door, when i got inside to start the car, but the key didnt even turn, everything was stiff, the steering locked, when i put the key in the ignition, nothing light up, I dont know if this has ever happened to anyone else, I dont know which battery is dead, the one in the boot or the one at the engine bay area.
Please advise
Please advise
When the voltage of the consumer battery in the trunk drops below a threshold it puts the car into hibernation. This happens after 2 or 3 days. Then you have to unlock the car with the key blade, and it's a bit of a pig, but when you insert the fob and turn it the starter battery has enough juice to turn on the instruments and start the car. Then after a decent period running, everything gradually comes back... The essentials instantly and the toys later.
The fact you have nothing says both batteries are dead. If they're in warranty return them otherwise budget for new ones.
Super Member
Joined: Oct 2023
Posts: 543
Likes: 191
W221 S500
You need to charge your batteries. The first suspect (for the key) is the smaller aux battery. For giggles - you can hook some jumper cables to another (running) car and see if the voltage enables the key. If you can then start the car - maybe just maybe the alternator will charge the system up.
You might get lucky, but...
MBWorld Fanatic!
Joined: Feb 2012
Posts: 2,613
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From: Phoenix
222 S-65
OP if both batteries are (and have been for months) dead they are not returning to life with a charge.
Do also verify that the fob battery is alive.
Fresh batteries and a few prayers she may just light up and not greet you with a plethora of undervoltage codes.
A battery maintainer is the solution in the future. Mercedes offers one.
Do also verify that the fob battery is alive.
Fresh batteries and a few prayers she may just light up and not greet you with a plethora of undervoltage codes.
A battery maintainer is the solution in the future. Mercedes offers one.
Super Member
Joined: Oct 2023
Posts: 543
Likes: 191
W221 S500
OP if both batteries are (and have been for months) dead they are not returning to life with a charge.
Do also verify that the fob battery is alive.
Fresh batteries and a few prayers she may just light up and not greet you with a plethora of undervoltage codes.
A battery maintainer is the solution in the future. Mercedes offers one.
Do also verify that the fob battery is alive.
Fresh batteries and a few prayers she may just light up and not greet you with a plethora of undervoltage codes.
A battery maintainer is the solution in the future. Mercedes offers one.
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MBWorld Fanatic!
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From: Phoenix
222 S-65
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MBWorld Fanatic!
Joined: Aug 2021
Posts: 1,536
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1983 Nissan Shltbox
to warranty-out batteries you destroyed would be unethical. why should i have to pay for someone else's immorality?
bro, you have no anything because you killed your batteries. you don't need us to tell you that, do you?
bro, you have no anything because you killed your batteries. you don't need us to tell you that, do you?
Super Member
Joined: Oct 2023
Posts: 543
Likes: 191
W221 S500
Why put a 3/4/5 year warranty on a battery if it doesn't last that long? That's the definition of a warranty... To replace something if it fails before it should. Doesn't matter if it's a loaf of bread that goes mouldy before the expiration date or a battery.
MBWorld Fanatic!
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1983 Nissan Shltbox
You won't win this one, bro.
Super Member
Joined: Oct 2023
Posts: 543
Likes: 191
W221 S500
First thing I had to do to mine was replace both batteries... Previous owner had fitted 2 MB AGM batteries 6 months prior but the history was lost, so no comeback for me.
One of the Bosch batteries I fitted to replace the MB ones failed 18 months into its 4 year guarantee. Went straight back and they added the balance to the replacement.
Last edited by AL5461; Mar 18, 2026 at 03:27 PM.
MBWorld Fanatic!
Joined: Aug 2007
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From: Pacific Northwest
2001 S600 V12 Sold, 2011 Jaguar XFR Sold, 2017 S550 4-Matic, 2018 S63 AMG Sedan
I'm with @Senecat on this one. Why should a manufacturer pay for something that was abused? If the battery was maintained proplerly it wouldn't have failed, probably. But left on a constant drain with no charge for months is not how a regular car battery is supposed to be used. These batteries re not deep-cycle batteries. Man up and pay the piper for your mistake. As a former importer and distributor, I got fed up with people abusing my products and saying there's a manufacturing defect.
MBWorld Fanatic!
Joined: Aug 2021
Posts: 1,536
Likes: 765
1983 Nissan Shltbox
It's not a competition, if they're under warranty, they're fair game, if they're not, it's a $600 lesson.
First thing I had to do to mine was replace both batteries... Previous owner had fitted 2 MB AGM batteries 6 months prior but the history was lost, so no comeback for me.
One of the Bosch batteries I fitted to replace the MB ones failed 18 months into its 4 year guarantee. Went straight back and they added the balance to the replacement.
First thing I had to do to mine was replace both batteries... Previous owner had fitted 2 MB AGM batteries 6 months prior but the history was lost, so no comeback for me.
One of the Bosch batteries I fitted to replace the MB ones failed 18 months into its 4 year guarantee. Went straight back and they added the balance to the replacement.
Last edited by Senecat; Mar 18, 2026 at 05:38 PM.
