Your might want a new key for your Mercedes, either as a spare copy or a replacement for a lost or stolen set. Since Mercedes uses smart key technology--a high-end transponder key--the key must be programmed for the specific car that you own. This involves purchasing a key from the dealership. It is expensive and can take up to three weeks. Mercedes requires the codes for each car to be ordered directly from the company, and you will have to provide certification that you own the car to the dealership. This wait for a car key is extraordinary, but it's a extra measure of security provided by Mercedes-Benz for your car and is required by all Mercedes dealerships.
Call your dealership and make them aware that you need a spare key. Be prepared for the price to be very high--as of 2010 perhaps £97 to £130. The keys must be ordered from the manufacturer and, unlike almost every other brand of car, must be programmed by the manufacturer to work. The dealership will advise you on what type of paperwork they require you to bring in order to obtain your key.
Bring your paperwork into the dealership. Generally Mercedes requires that you bring in the car's documentation and proof of purchase plus a photo ID. You will pay for the key when you place the order. After verifying your ownership, the dealer will order your key. Generally it will take two to three weeks for the key to arrive. Some dealerships will require you to leave your car at their location while the key is on order.
Pick up your key when it arrives at the dealership. You will be required to show your identification at this point as well. Since you will have paid for the key upon ordering, you should not be required to pay any additional fees.
If your key has stopped working, try changing the battery before you call the dealership. If your dealership requires you to leave your car for the waiting period, consider using an import specialist to order your key. You will still need to verify your ownership of the car, but generally they do not require you to leave your car with them. Look for a specialist that services BMW, Aston-Martin, Saab, Mercedes and other import brands.
Under no circumstances buy a key online. The only way you can get a Mercedes key online is if it is used. These keys are not available for reprogramming and will not be serviced by either a locksmith, a dealership or an import specialist.