Coded car keys are now standard in virtually all modern vehicles.
In addition to protecting the vehicle against unauthorised copies, they are essential for starting the engine. However, when they are lost or need to be duplicated, the process is more complex than with a conventional key.
In this article, find out what coded car keys are, how they work and what to do if you lose them.
What Is a Coded Car Key?
A coded car key is a vehicle key that contains an electronic chip (transponder) inside the key head. This chip emits a unique code that communicates with the vehicle’s ECU.
When the key is inserted into the ignition, the immobiliser checks whether the code matches the one stored in the vehicle. If it does not match, the engine will not start, even if the physical key blade has been cut correctly.
How Does a Coded Car Key Work?
When the key is placed in the ignition, the immobiliser coil, located around the ignition barrel, emits a short-range radio-frequency signal. This signal powers the key’s chip and requests the stored code.
During this process, the ECU compares the received code with the one stored in the vehicle. If they match, the immobiliser is deactivated and the engine can start.
In keys with remote controls, this process works alongside the central locking system. Keyless entry keys work in a similar way, but use Bluetooth or longer-range radio frequency, meaning there is no need to insert the key into the ignition.
How Can You Find The Code For a Coded Car Key?
The code for a coded car key can be found in several ways:
1. Vehicle Manufacturer Documentation
The code may be included in the documents supplied when the vehicle was purchased, on a label attached to the owner’s manual or on a separate card.
2. Printed On The Key
Some keys have the code printed or engraved on the metal or plastic part of the key.
3. Metal Plate In the Glovebox
Some vehicles have a metal plate containing the immobiliser code located near the VIN or fuse box. Be careful not to confuse this with the vehicle’s VIN.
4. Dealership Or Manufacturer
After providing identification documents and proof of vehicle ownership, the dealership may be able to access the code using the vehicle’s serial number or VIN.
5. Specialist Car Key Centre
Automotive locksmiths have specialised software that allows them to read and programme immobiliser codes for most makes and models.
What Should You Do If You Lose Your Coded Car Keys?
Losing a coded car key is more complicated than losing a conventional key because, without the original code, it is not possible to make a direct copy.
To deal with this situation:
1. Check Whether You Have a Spare Key
If you have a spare, take it to an automotive locksmith, as they may be able to make a copy without needing the original code.
2. Contact Your Insurance Company
If your car insurance policy covers lost keys, the insurer may cover part or all of the replacement cost.
If the keys were damaged in an accident, a vehicle damage assessment may also be required to validate the damage with the insurer.
3. Contact the Dealership Or Manufacturer
With proof of vehicle ownership and identification, the dealership can order a new key from the manufacturer and programme it for your vehicle.
4. Contact a Specialist Automotive Locksmith
Independent specialist centres can, in many cases, programme a new key without the original by using the code obtained through vehicle immobiliser diagnostics.
The process is similar to ECU remapping, as it requires specialised software and access to the vehicle’s ECU.
Is It Possible To Make a Coded Car Key Without The Original?
Yes, but specialised equipment is required.
A technician with access to immobiliser diagnostic software can read the code directly from the vehicle’s ECU and programme a new key without the original. For security reasons, however, this can only be carried out after proof of vehicle ownership has been provided.
As a general rule, this process takes longer and costs more than making a copy using an original key.
How Long Does It Take To Make a Coded Car Key?
The time required varies depending on the method and the availability of the parts.
Generally, copying a car key using the original key can take up to 60 minutes. If a key has to be programmed without the original, the process can take up to 3 hours.
When the coded key needs to be ordered from a dealership or manufacturer, the process can take up to 7 working days. This period can increase to 2 weeks for luxury or rare vehicle brands.
How Much Do Coded Car Keys Cost?
The cost depends on the method, make and model of the vehicle.
Copying a key using an original can cost anywhere from tens to hundreds of euros, depending on the make and model. Programming a key without the original can cost several hundred euros.
When the key has to be ordered from a dealership or manufacturer, the cost can approach thousands of euros, including the key itself and programming.
How Can You Avoid Problems If You Lose Your Coded Car Keys?
As with preventive vehicle maintenance, anticipating a problem is always cheaper than dealing with a breakdown.
Therefore:
- Always make a spare key before losing the original, as making a copy with the original key costs much less than programming a new one without it;
- Check whether you have a used-car warranty that covers key replacement, as some situations may be covered;
- Keep the key documentation in a safe place away from the vehicle, as the code may be essential for future programming;
- Record the key’s serial number or code in a secure location, such as a home safe or password manager;
- Check whether your insurance covers lost keys, as many policies include this cover or allow it to be added at a low cost;
- Never keep both keys in the same place, as losing one means the second can be used as a starting point for a faster and cheaper replacement.
Where Can You Get Coded Car Keys Made?
Coded car key services are available through several types of providers across Europe. Requirements, procedures and costs can vary by country, so always check the applicable local legislation and requirements.
Specialist Automotive Locksmiths
Available in most cities, these professionals have the equipment required to programme keys for the most common vehicle brands.
They are generally faster and less expensive than dealerships.
Dealerships and Authorised Workshops
They have direct access to the manufacturer’s systems, making them a suitable option for newer vehicles or models with more complex security systems.
The cost is generally higher than with other options.
Automotive Diagnostic Centres
Some centres with advanced diagnostic equipment can read and reprogramme immobiliser systems without the need for the original key.
This option can be useful when no spare key is available.
Where Can You Get Coded Car Keys Made For Your Car?
For any of the options above, look for centres with proven experience with your vehicle’s make and model.
Before authorising the work, request a detailed quote, as prices can vary significantly between providers.
In any case, be wary of prices that are significantly below the market average, particularly for coded key programming without the original key.
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