Mercedes-Benz Dead Key Fob Help

Getting into Your Mercedes-Benz

Retrieving the mechanical key

Mercedes key fobMercedes-Benz now features two SmartKey styles. The original and most common style is tapered, like the one shown to the right. To retrieve the mechanical key, slide the release catch found near the top of the fob in the direction of the arrow and pull the mechanical key away from the SmartKey (remote control or ‘clicker’).

New Mercedes key fobThere much more below and video help here


In 2017, a second, rounded SmartKey style was introduced in the E-Class sedan, and is shown to the right. It migrated to S-Class sedans in 2018 and is found in all 2018 E-Class models.

Look for a button on the back of the newer key fob. Push the button and pull on new mechanical keythe key ring end to remove the mechanical key, as shown in the image to the right.

If the keyhole is visible, use the mechanical key to unlock the driver’s door. This will set off the car’s alarm.  Successfully completing the start process below will turn it off.

Beginning in 2015 with the S- and C-Class vehicles and extended in 2016 to the GLE, the keyhole is hidden beneath a cap at the end of the driver’s door handle (below right). The mechanical key will be used a lever to remove the cap to expose the key hole.

Mercedes lock coverMake sure the handle of the mechanical key is pointed away from the paint. Insert the key into the opening (black arrow) underneath the cap as far as it will go. Hold the door handle out. Pull the cap that is now on the mechanical key as straight as possible away from the vehicle until it releases.

Once removed, the key hole is visible and available to insert the key and unlock. As above, this will set off the car’s alarm, which will be taken care of when you successfully complete the start process below.

Click here for video help specific to Mercedes models and key fobs.

After using the mechanical key, return it to the electronic key fob. The key fob itself may require the mechanical key to be present to operate.

Starting Your Mercedes-Benz

Mercedes Start ButtonTo start a Mercedes-Benz that uses the tapered SmartKey style, the engine Start / Stop ignition button must be removed. It appears to ‘float’ above the dashboard and is easily pulled away from the ignition lock. Insert the tapered end of the KEYLESS-GO key in the ignition lock and turn it to start and operate old school style.

AMG ignition lockBeginning in 2017, the ignition lock in AMG roadsters and coupes is found at the back of the center console storage area, as shown in the image. Insert the tapered key fob into the ignition lock and turn it to start and operate old school style.


Models using the new, rounded SmartKey style, require that the SmartKey be placed in a back up location or slot. Do NOT attempt to remove the Start / Stop ignition button!

Mercedes back up slotThe slot is found just in front of the cup holders on the center console. It is marked by the image of a key with lines radiating from it, as shown in the image. Note that the slot is smaller and to one side in E-Class models, but is marked in the same way.

Slide the SmartKey into the slot with its buttons up and start as normal. The car will recognize the key fob even if its internal battery is dead.

Note: If you have made an attempt to start the vehicle without success, there may be residual pressure in the brake system and a new warning light may appear (left) or text Engine Start Operation Indicatormessage to Step on the Brake. Press the brake pedal very, very hard when trying to start the vehicle again to be sure that the release switch behind the pedal is engaged. Check out this page for more!

Click here for video help specific to Mercedes models and key fobs.


* Keep these instructions with you in our Dead Key FOB App. Search “Dead Key FOB” at your device’s store or click here.

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