How to Repair a Mercedes Key Fob

by Tiffany Raiford
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car key #5 image by Adam Borkowski from

Mercedes key fobs are known as SmartKeys. Every late-model Mercedes-Benz vehicle is equipped with a SmartKey, which allows you to lock and unlock your doors without touching your car keys. When you are close enough to your Mercedes vehicle with your SmartKey, you can push the button located on the door handle and your doors will lock and/or unlock automatically. If your SmartKey is not working, there are several do-it-yourself repairs available to repair your SmartKey you can try before contacting your Mercedes-Benz dealer for an appointment.

Step 1

Replace the battery in your SmartKey. Purchase a new battery at any auto parts store or any authorized Mercedes-Benz dealership. Open the SmartKey fob using a sharp object, such as a butter knife, and trade out the dead battery for the new battery. Test the SmartKey remote.

Step 2

Repair a SmartKey that no longer starts your car's engine by turning off all of the non-essential functions in your car, such as lights, the radio and the heated seats, then try to start the ignition. Jump-start your car if this does not work and contact your Mercedes-Benz service department for a repair appointment.

Step 3

Pull the door handle of your Mercedes and turn your SmartKey to the second position in the ignition. Use this method if you cannot lock or unlock your car with the remote.

Step 4

Contact Mercedes-Benz. The Mercedes-Benz website allows you to enter your zip code to find the dealership nearest your location.

Step 5

Explain that your key fob is not working correctly. Be as specific about the problem as you can. For example: tell the dealership if your key fob only works when you are unlocking your doors and not for anything else. The more specific you are, the better Mercedes can diagnose your fob's issue.

Step 6

Attempt to fix your key fob if the mechanic at Mercedes tells you to try any self-diagnostics on the fob. Sometimes the mechanic recognizes the problem without ever seeing the fob, based on your description of the problem and will walk you through the repair process. If he or she cannot, you'll need to take your key to Mercedes for repair.

Step 7

Take your key to Mercedes if self-diagnostics you tried on your own and/or that the mechanic advised you to try do not work. From this point the process is up to Mercedes, such as how long you need to wait, whether or not your fob is fixable or you'll need to order a new one and how much the repair/replacement will cost you.

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