SmartKey

SmartKey with remote control

W220s sold in the US and Canada have a panic button on the SmartKey keyfob. W220s sold elsewhere in the world do not have a panic button.

Frequencies for central locking are:

In Europe 433.92 MHz
In USA 315.00 MHz

(1) Lock button
(2) Unlock button for trunk lid
(3) Unlock button
(4) Panic button

Panic alarm

If panic button is pressed an audible alarm and flashing exterior lamps will operate for approximately 2.5 minutes.

To activate press and hold button (1) for at least one second. To deactivate press button (1) again or insert SmartKey in starter switch.

Replacing batteries

Replacement batteries: Lithium, type CR 2025 or equivalent.

Remove mechanical key (1).
Insert the mechanical key (1) in side opening and push gray slide. The battery compartment is unlatched.
Pull the battery compartment (2) out of the SmartKey housing in direction of arrow.
Remove the batteries.
Using a lint-free cloth, insert new batteries (3) under the contact spring (4) with the plus (+) side facing up.
Return battery compartment into housing until it locks into place.

In case of KEYLESS-GO the SmartKey contains only a single battery on the other side.

SmartKey battery replacement.

Replacing broken shell

After long years of use the buttons on shell cover of SmartKey can develop cracks. There are replacement shells available on ebay for as cheap as 3 EUR, the only visual difference of ebay replica is the lack of MB chrome star on the back of the shell.

The problem with this cheap replica is that buttons are quite hard to press and the size of cover is 0.5 mm thicker than the original (see the photos below). This requires to apply quite significant force to push the eBay SmartKey into the electronic ignition switch (EIS).

Warning: do not use the method shown below for pulling out board for SmartKey with KEYLESS-GO, because the hook will damage the coil that is centered on the board.