I have a 2012 SLK 200 with a locking problem sometimes when I return to open the car door with the key fob it will not open I have tried it with the spare key and it. The same with the spare key

You need to visit an auto electrician, an alarm installer or an auto locksmith. The key fob needs re-pairing to the locking system.

Videos that might help

https://www.google.com/search?q=2012+Dodge+Charger.+Key+fob+not+locking+and+unlocking+doors+after+battery+change

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sadly I must tell you this forum is answered by mostly old DIYER"s and do not know every trick about every problem that the world has , so suggest only you see a dealer locally of your Make of vehicle. it could be as simple as the bcm needs reprogrammed .which only dealers can do

Try the auto manufacturers 30 minute security reset.

Search "chrysler security reset" for instructions.

May be keyfob needs reprogramming.

Keyfob remote reprogramming is not very difficult but on some cases it can be done by dealer service tools.

If the remote s faulty then key fob will not get programmed.

Insert the key in ignition. Turn the key to on position, and cycle the key three times off-on-off-on-off-on. Then with the key fob remote select your remote and then try to operate the vehicle with remote.

These are just the basic procedure, but sometimes it will not help.

On that case dealer is the only option.

---------

There are few much related troubleshooting links mentioned below for remote key fob reprogramming. I suggest you to go through the list and click the link below to go through its details and procedure: -------

Theft indicator not letting car to start?

http://technoanswers.blogspot.in/2012/02/theft-indicator-not-letting-car-to.html

-------------

2009 Toyota Highlander: Smart Key Not getting Detected?

http://whatisbyme.blogspot.in/2012/05/2009-toyota-highlander-smart-key-not.html

----------

2007 Toyota Prius: Reprogram Remote Keyfob?

http://whatisbyme.blogspot.in/2012/05/2007-toyota-prius-reprogram-remote.html

-----------

Pin that holds the flick key part to the key fob?

http://whoisbyme.blogspot.in/2012/07/pin-that-holds-flick-key-part-to-key-fob.html

-------------

2006 Toyota Hilux: Programming New Key?

http://technoanswers.blogspot.in/2012/04/2006-toyota-hilux-programming-new-key.html

----------

Where is Key chip memory located on 2004 ford Freestar?

http://technoanswers.blogspot.com/2012/01/where-is-key-chip-memory-located-on.html

----------

Ford Keyless Remote Fob Reprogramming?

http://schematicsdiagram.blogspot.com/2011/12/ford-keyless-remote-fob-reprogramming.html

----------

After getting car washed, check engine light is ON and key less entry not working, tried reprogramming. Also car shows fuel pressure?

http://schematicsdiagram.blogspot.com/2011/12/after-getting-car-washedcheck-engine.html

-----------

Audi A8 Key Fob Programming?

http://technoanswers.blogspot.com/2011/12/audi-a8-key-fob-programming.html

----------------

Oldsmobile Aurora Key Fob Reprogramming?

http://technoanswers.blogspot.com/2011/12/olds-aurora-key-fob-reprogramming.html

-------------

Buick Lesabre Key Fob Reprogramming?

http://technoanswers.blogspot.com/2011/12/buick-lesabre-key-fob-reprogramming.html

---------------

Keyfob remote not working on 2003 Ford E350 Econoline?

http://technoanswers.blogspot.in/2012/01/keyfob-remote-not-working-on-2003-ford.html

-----------

KeyFob will open the doors but not start on BMW?

http://technoanswers.blogspot.in/2012/02/key-will-open-doors-but-not-start-on.html

------------

Mitsubishi Car Key Not getting detected after replacing ECM

http://repairhelpcenter.blogspot.com/2012/11/mitsubishi-car-key-not-getting-detected.html

-----------

Key Fob will not lock and unlock doors?

http://technoanswers.blogspot.in/2012/02/key-fob-will-not-lock-and-unlock-doors.html

-------------

2000 Jeep Cherokee Limited: KeyFob Remote Not Working?

http://schematicsdiagram.blogspot.in/2012/06/2000-jeep-cherokee-limited-keyfob.html

-----------

Chevrolet Malibu: Key Stuck in ON position?

http://technoanswers.blogspot.in/2012/04/chevrolet-malibukey-stuck-in-on.html

-----------

2012 Dodge Ram: Ignition Key will not release?

http://whoisbyme.blogspot.in/2012/07/2012-dodge-ram-ignition-key-will-not.html

--------------

These details will help.

Thanks.

Try with brand new key fob battery and see.If that helps.
Otherwise May be keyfob needs to be reprogrammed.

KEYFOB PROGRAMMING

Keyfob remote reprogramming is not very difficult but on some cases it can be done by dealer service tools.

If the remote s faulty then key fob will not get programmed.

Insert the key in ignition. Turn the key to on position, and cycle the key three times off-on-off-on-off-on. Then with the key fob remote select your remote and then try to operate the vehicle with remote.

These are just the basic procedure, but sometimes it will not help.

On that case dealer is the only option.

---------

There are few much related troubleshooting links mentioned below for remote key fob reprogramming. I suggest you to go through the list and click the link below to go through its details and procedure: -------

2009 Toyota Highlander: Smart Key Not getting Detected?

http://whatisbyme.blogspot.in/2012/05/2009-toyota-highlander-smart-key-not.html

----------

2007 Toyota Prius: Reprogram Remote Keyfob?

http://whatisbyme.blogspot.in/2012/05/2007-toyota-prius-reprogram-remote.html

-----------

Pin that holds the flick key part to the key fob?

http://whoisbyme.blogspot.in/2012/07/pin-that-holds-flick-key-part-to-key-fob.html

-------------

2006 Toyota Hilux: Programming New Key?

http://technoanswers.blogspot.in/2012/04/2006-toyota-hilux-programming-new-key.html

----------

Where is Key chip memory located on 2004 ford Freestar?

http://technoanswers.blogspot.com/2012/01/where-is-key-chip-memory-located-on.html

----------

Ford Keyless Remote Fob Reprogramming?

http://schematicsdiagram.blogspot.com/2011/12/ford-keyless-remote-fob-reprogramming.html

----------

After getting car washed, check engine light is ON and key less entry not working, tried reprogramming. Also car shows fuel pressure?

http://schematicsdiagram.blogspot.com/2011/12/after-getting-car-washedcheck-engine.html

-----------

Audi A8 Key Fob Programming?

http://technoanswers.blogspot.com/2011/12/audi-a8-key-fob-programming.html

----------------

Oldsmobile Aurora Key Fob Reprogramming?

http://technoanswers.blogspot.com/2011/12/olds-aurora-key-fob-reprogramming.html

-------------

Buick Lesabre Key Fob Reprogramming?

http://technoanswers.blogspot.com/2011/12/buick-lesabre-key-fob-reprogramming.html

---------------

Keyfob remote not working on 2003 Ford E350 Econoline?

http://technoanswers.blogspot.in/2012/01/keyfob-remote-not-working-on-2003-ford.html

-----------

KeyFob will open the doors but not start on BMW?

http://technoanswers.blogspot.in/2012/02/key-will-open-doors-but-not-start-on.html

------------

Mitsubishi Car Key Not getting detected after replacing ECM

http://repairhelpcenter.blogspot.com/2012/11/mitsubishi-car-key-not-getting-detected.html

-----------

Key Fob will not lock and unlock doors?

http://technoanswers.blogspot.in/2012/02/key-fob-will-not-lock-and-unlock-doors.html

-------------

2000 Jeep Cherokee Limited: KeyFob Remote Not Working?

http://schematicsdiagram.blogspot.in/2012/06/2000-jeep-cherokee-limited-keyfob.html

-----------

Chevrolet Malibu: Key Stuck in ON position?

http://technoanswers.blogspot.in/2012/04/chevrolet-malibukey-stuck-in-on.html

-----------

Theft indicator not letting car to start?

http://technoanswers.blogspot.in/2012/02/theft-indicator-not-letting-car-to.html

-------------

2012 Dodge Ram: Ignition Key will not release?

http://whoisbyme.blogspot.in/2012/07/2012-dodge-ram-ignition-key-will-not.html

--------------

These details will help.

Thanks.

Keyfob remote reprogramming is not very difficult but on some cases it can be done by dealer service tools.If the remote s faulty then keyfob will not get programmed.Insert the key in ignition.Turn the key to on position,and cycle the key three times off-on-off-on-off-on.Then with the keyfob remote select your remote and then try to operate the vehicle with remote.These is just the basic procedure,but sometimes it will not help.
On that case dealer is the only option.
---------There are few very relted troubleshooting links mentioned below for remote key fob reprogramming.I suggest you to go through the list and click the link below to go through its details and procedure:-------
2009 Toyota Highlander: Smart Key Not getting Detected? http://whatisbyme.blogspot.in/2012/05/2009-toyota-highlander-smart-key-not.html
----------2007 Toyota Prius: Reprogram Remote Keyfob? http://whatisbyme.blogspot.in/2012/05/2007-toyota-prius-reprogram-remote.html
----------- Pin that holds the flick key part to the key fob? http://whoisbyme.blogspot.in/2012/07/pin-that-holds-flick-key-part-to-key-fob.html
-------------
2006 Toyota Hilux: Programming New Key? http://technoanswers.blogspot.in/2012/04/2006-toyota-hilux-programming-new-key.html
----------Where is Key chip memory located on 2004 ford Freestar? http://technoanswers.blogspot.com/2012/01/where-is-key-chip-memory-located-on.html
----------Ford Keyless Remote Fob Reprogramming?

http://schematicsdiagram.blogspot.com/2011/12/ford-keyless-remote-fob-reprogramming.html
----------After getting car washed, check engine light is ON and key less entry not working, tried reprogramming. Also car shows fuel pressure? http://schematicsdiagram.blogspot.com/2011/12/after-getting-car-washedcheck-engine.html
-----------Audi A8 Key Fob Programming?

http://technoanswers.blogspot.com/2011/12/audi-a8-key-fob-programming.html

----------------
Oldsmobile Aurora Key Fob Reprogramming?

http://technoanswers.blogspot.com/2011/12/olds-aurora-key-fob-reprogramming.html

-------------
Buick Lesabre Key Fob Reprogramming?

http://technoanswers.blogspot.com/2011/12/buick-lesabre-key-fob-reprogramming.html

---------------
Keyfob remote not working on 2003 Ford E350 Econoline?

http://technoanswers.blogspot.in/2012/01/keyfob-remote-not-working-on-2003-ford.html

-----------
KeyFob will open the doors but not start on BMW?

http://technoanswers.blogspot.in/2012/02/key-will-open-doors-but-not-start-on.html

------------
Mitsubishi Car Key Not getting detected after replacing ECM http://repairhelpcenter.blogspot.com/2012/11/mitsubishi-car-key-not-getting-detected.html
----------- Key Fob will not lock and unlock doors?

http://technoanswers.blogspot.in/2012/02/key-fob-will-not-lock-and-unlock-doors.html

-------------
2000 Jeep Cherokee Limited: KeyFob Remote Not Working? http://schematicsdiagram.blogspot.in/2012/06/2000-jeep-cherokee-limited-keyfob.html
----------- Chevrolet Malibu: Key Stuck in ON position? http://technoanswers.blogspot.in/2012/04/chevrolet-malibukey-stuck-in-on.html
----------- Theft indicator not letting car to start?

http://technoanswers.blogspot.in/2012/02/theft-indicator-not-letting-car-to.html

-------------
2012 Dodge Ram: Ignition Key will not release? http://whoisbyme.blogspot.in/2012/07/2012-dodge-ram-ignition-key-will-not.html
--------------
These details will help.Thanks.

no good needs replaced

Troubleshooting is required to inspect few parts.It can be issue with ignition switch.Its not getting off.Or issue with sensor or wiring.Or its faulty lock itself.Click the link below and follow the troubleshooting:----Driver Door will not lock or unlock with Key or Remote? http://whatisbyme.blogspot.in/2012/05/1998-toyota-landcruiser-driver-door.html
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Driver side door will not lock or unlock with Remote? http://technoanswers.blogspot.in/2012/04/2009-toyota-tundra-driver-side-door.html
---------
Central locking not working ? http://schematicsdiagram.blogspot.in/2012/03/this-is-how-system-operates.html

--------------
Remote will not unlock Rear door ?
http://schematicsdiagram.blogspot.com/2011/12/remote-will-not-unlock-rear-door-on-gmc.html

---------

Repairing car Door lock Actuator?
http://howtobyme.blogspot.com/2011/11/repairing-car-door-lock-actuator.html

--------

How to Access car door panel?
http://howtobyme.blogspot.com/2011/11/how-to-access-car-door-panel.html

-----

Vehicle door panel components?
http://howtobyme.blogspot.com/2011/11/vehicle-door-panel-components.html

-----------
This will help.
Thanks.

this sounds like a door switch not switching if you shut the door and left your kyes inside the car the door locks would pop up so you cant look yourself out,,,(but you can?) my money is on a door switch,, give them all a good swilling with WD40 to free them off if this dont fix it then its the car alarm it needs to be reprogramed to the kye fob and also fit a new battery to the kye fob at the same time people often forget how much work the kye fob needs to do and only when it stops working do they change the battery in it,