Mercedes Key Replacement: Who Can Do It and What It Costs

Which keys does Mercedes use?

Mercedes moved away from a conventional cut key early. From the late 1990s many models used an infrared key: a plastic-bodied key, often with a chrome tip, that slots into the ignition and talks to the car by infrared rather than turning a barrel with a cut blade. Later came smart-key fobs, still inserted on some models, and KEYLESS-GO, which unlocks and starts the car with the fob left in a pocket. A small emergency blade hides inside most fobs for the door. Behind every one sits Mercedes' own drive authorisation system, known as FBS, which has been through several generations.

Can an independent auto locksmith make a Mercedes key?

It depends on the generation. Locksmith trade sources agree that the FBS4 system, introduced from around 2015, uses encryption tied to Mercedes' own servers, and that most independent locksmiths cannot programme a new key for it; the key is ordered through a dealer against the car's identity. Keys for older systems, including many infrared keys, are routinely replaced or repaired by independent specialists. Some reports say Mercedes has opened limited dealer-level access to independent workshops, but this site has not confirmed how widely. Give the locksmith your registration and model year and ask directly whether they can do your car before anyone travels.

Does SERMI change things for Mercedes owners?

SERMI is the scheme that gives checked independent workshops and auto locksmiths a route to manufacturers' security data. It went live in the UK on 1 April 2026, run by RMI Standards and Certification, with Ford, Jaguar, Land Rover, Nissan and Toyota as the first brands. CAT Magazine named Mercedes-Benz among the manufacturers backing the scheme at its UK launch. Backing a scheme is not the same as every key being open to independents, and FBS4 work may still route through Mercedes. If a locksmith says they hold a SERMI certificate, ask to see it, since no public list of members has been found.

What should you have ready?

Expect to prove the car is yours before anyone cuts or orders a key. Have the V5C logbook in your name, photo ID such as a passport, and something showing your address. If the keys were stolen, report it to the police and keep the crime reference; the old key should also be taken off the car's memory. For a dealer order, Mercedes works from the vehicle identification number, so the VIN on the V5C and on the car must match. A note of how many keys came with the car helps as well.

What does a Mercedes key cost?

There is no sourced Mercedes-only figure. Across makes, a replacement key cut and programmed costs £100 to £282: the lower end is StageMyCar's locksmith floor, and the upper end is the average WhoCanFixMyCar records from its 2026 bookings. Programming alone averages £250 on WhoCanFixMyCar. StageMyCar, a trade blog given less weight here, says dealers often charge more than independents, and Mercedes keys tend to sit high because newer cars go through the dealer. Ask for a written price that includes the key, the programming and any call-out.

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