What is the cost of a Mercedes Benz replacement key?


The following article will explain the programming of Mercedes Benz replacement keys and answer the following questions: What is the price of a Mercedes Benz replacement key? What is the difference between a replacement key and an additional key?

What is the cost of a Mercedes Benz replacement key?

The Genuine Mercedes Benz replacement key can cost from 400 to 600 $ depending on the Model series. The cost of a Mechanical key is not included in the cost of a digital key fob and it must be ordered separately. Depending upon which drive authorization system generation is present on the vehicle the replacement key can be programmed at the dealership or a pre-programmed key can be ordered directly from the factory.

The digital Key fob of vehicles with Keyless go systems are expensive when compared to vehicles without keyless go or keyless start systems. Keyless go utilises additional antennas in door handles and the interior of the vehicle. Hence the Key fob has to be built in with a transmitter and a receiver to receive signals from the Keyless go antennas. The effective range of Keyless go antennas is around 2 metres. 

 When Key comes within the range of anyone’s antenna, a drive authorization signal is requested after pressing the start-stop switch or by touching on the capacitive sensors present on door handles. As the keyless go system is connected directly to the main battery, antennas are always active and scanning for keys in a range of 2 metres.

In a Mercedes Benz vehicle a drive authorization system consists of four to five theft relevant components. Each time a driver inserts a key fob into the vehicle a drive authorization code is verified in all theft relevant components, the vehicle will only start when the code is verified by these components and a start enable signal is received by the vehicle onboard computer.  

What is an Additional Key and replacement key?

Programming of key incorporates assigning a key to a specific key track that is present in the electronic ignition key. This is done by a diagnostics tool or at a key station available at the authorised service centre. Each vehicle has eight key tracks and consists of three segments but only one key fob can be used at any given time on an individual key track. 

This means a vehicle can have a total of twenty-four keys during the entire service life of the vehicle. In the event of a lost or stolen key, there is a way to identify the key track and block it so misuse of the key fob can be prevented. This key track can be activated again if a customer finds the key.

Replacement Key

If a customer cannot find the lost/ stolen key then it is possible to programme a new key fob to the same key track but new segment 2. This will make the old key fob inoperative and the new key will act as a replacement key. Even if the customer finds the original key, it is no longer possible to use it since a replacement key has already been programmed in the electronic ignition switch control unit.

Additional Key

When a customer requests more than two keys for the vehicle, it is possible to programme a key fob to a different key track. This way the existing two keys will remain operational and the customer will gain an additional key for the vehicle. A Vehicle can have six additional keys in addition to the two original keys which comes as standard.

The time required to programme replacement key is more when compared to programming additional key. There is no difference in the cost of the additional key and replacement key, as it is the programming in the EZS electronic ignition lock control unit which determines how the Key is being used.

The latest drive authorization system (DAS) is generation 4 which allows for remote programming of key fobs at authorised dealerships which will greatly reduce repair times as dealerships can keep blank, unprogrammed keys in their stock. DAS 4 also allows the use of Smartphones to lock and unlock newer models.

If both the keys are lost then it is not possible to program keys at the dealership. At Least one working key must be present to program a replacement key. In such cases, dealerships can submit customer details and required documents to order a pre-programmed key from the factory.

The programmed key will complete initialization when inserted in the Electronic lock switch. The initialization can take up to a few hours depending on the number of replacement keys.

Common problems in Mercedes Benz Keys.

  • Low battery– the key uses up to 2 battery cells to transmit and receive drive authorization signals. A low battery can reduce the range of the key and in some cases make the key inoperative. Few Mercedes Benz Key fobs had a low battery indicator led on the key. Replace the battery if the key does not operate, if the key is still inoperative after replacing the battery; consult the workshop with both sets of Keys for further diagnosis.
  • switches -there are mechanical switches on the key fob, long use and exposure to elements can cause the switch to jam and become hard to operate. As individual child parts are not available for the key, it must be replaced.
  • Internal malfunction: The Key fob has a receiver to receive a wake-up signal from the keyless go antenna and a transmitter to transmit the signal. Any electrical fault can make the key inoperative or in some cases only locking and unlocking is a function but it is not possible to drive the vehicle.

Do not use unauthorised accessories like protective cases, colours and key rings on the key as it can limit the functionality of the key.

Key features of Mercedes Benz key.

  • Global or selective unlocking- In selective unlock it is possible to unlock only the driver’s door with one press of the unlock button. GLobal unlock all the doors of the vehicle. By holding down both lock and unlock switches it is possible to toggle between global and selective unlock feature
  • Comfort open and closing feature.- by holding the unlock switch it is possible to open all the windows and sunroof of the car. To close it, simply hold down the lock button until all the windows are closed. In old models, comfort open and close features used infrared signals from the key, Hence it only functioned when the key was very close to the vehicle.
  • Panic button- in some markets like Europe and USA pressing the panic button will activate all the horns and flash hazards lights. It is a type of Anti Theft function if someone is trying to steal the car.


Due to the Keyless go and special function built into the key, the Mercedes Benz replacement key is slightly more expensive when compared to other brands. However, a replacement key can be programmed or purchased from any authorised dealership if the original key is lost. It is also possible to block access to the vehicle from the lost or stolen key until the customer can locate it. 

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