Car Key Programming: Dealer, Locksmith and SERMI

What is car key programming?

Programming tells the car to accept a particular key. Most modern cars have an immobiliser: a chip in the key (a transponder) talks to the car, and the engine will not start unless the car recognises it. Remote buttons and keyless entry are paired separately on many cars.

Cutting is the mechanical part, shaping the blade to turn the lock. Programming is the electronic part. A key can be cut perfectly and still not start the car until it has been programmed, which is why a cheap blade from a key cutter often only opens the door.

Can an auto locksmith programme a car key, or do you need a dealer?

For many cars, an auto locksmith can do it. They connect diagnostic equipment to the car's port and add the new key, usually at the roadside. It is often quicker than a dealer, which may need to order a key from the maker.

The dealer is the route when:

- the car's maker only releases the security data through its own systems, and the locksmith does not have access - the car is under a warranty or lease that requires the dealer - the model is new enough that independent equipment does not yet cover it

Give the locksmith the make, model, year and registration when you call. They can say on the phone whether they can programme it.

What is SERMI, and why does it matter?

SERMI (Security-related Repair and Maintenance Information) is a scheme that lets approved independent operators, including auto locksmiths, reach a maker's key programming and immobiliser data. It went live in the UK on 1 April 2026, run by RMI Standards and Certification, and the first brands were Ford, Jaguar, Land Rover, Nissan and Toyota, as Motor Trader reported.

To be approved, a business's legal representative and each technician need a basic DBS check and no unspent convictions, and the business is audited, including at least one unannounced visit (Core Diagnostics' guide to the scheme). It is not a legal requirement for locksmith work generally, but the makers use it as their gate. For a car from those brands, ask whether the locksmith is SERMI approved and whether you can see the certificate.

How much does car key programming cost?

Programming alone averaged £250.33 on WhoCanFixMyCar bookings in 2026. A full replacement key, cut and programmed, costs about £100 to £282: the low end is StageMyCar's locksmith range, from a trade blog, and the high end is WhoCanFixMyCar's booking average of £281.78. StageMyCar puts dealer prices at £150 to £500 or more.

Adding a second key on the same visit is usually cheaper than coming back later. Ask for the price split into key, cutting and programming, and whether VAT is included.

What does the Crime and Policing Act 2026 change?

It makes it an offence to possess or supply electronic devices used to steal vehicles, such as key emulators. The Act received Royal Assent in March 2026, as Thatcham Research reported. There is a defence where a person had no intent and no suspicion that a device would be used for theft.

For a car owner, the practical point is simple. Legitimate programming equipment used to make keys for the registered keeper is the normal work of an auto locksmith. A locksmith who programmes keys without asking for the V5C logbook and ID is not checking who they are helping, so expect those questions, and treat them as a good sign.

Common questions