All Keys Lost: How Does an Auto Locksmith Make a New One?

A new key can be made with no original to copy

Yes — a locksmith does not need your old key, because the process is origination, not duplication. The mechanical cuts come from the key code, and the electronics are introduced to the car fresh.

Think of it as the difference between photocopying a document and retyping it from the master file. The key code is the master file: a manufacturer record of the exact cut depths for your car. With it, a precision cutting machine produces a blade as accurate as the one that left the factory. The second half is electronic: the transponder chip in the new key must be registered with the immobiliser, or the ECU will refuse to start the engine. Both halves are done at the car, from the van — the vehicle does not need to move.

Step one is always proof of ownership

Expect to show the V5C logbook and photo ID before any cutting begins. A genuine locksmith checks; treat a skipped check as a reason to walk away.

This is not bureaucracy — it is the line between a legitimate trade and car theft. The check is simple: the V5C shows who the registered keeper is, and photo ID, usually a driving licence, shows you are that person. Names and addresses should match. If the V5C is lost as well, say so on the call — there are other ways to establish ownership, but nothing gets cut until it is settled. Be blunt with yourself here: any operator happy to make a key with no questions asked is someone you should not let near your car. The check protects you as much as anyone.

How the key code becomes a working blade

The key code is retrieved through legitimate, audited trade channels, then a code-cutting machine mills a fresh blade to those exact depths.

The VIN identifies your car — make, model, year — which tells the locksmith which blank to use and which procedure applies. The key code itself is separate, restricted data, released only against verified ownership. Once retrieved, the code goes into a precision cutter, which is far more accurate than tracing a worn key by hand. Laser-cut (sidewinder) blades need specialist kit, which is one reason the van matters. The cutting method always depends on the key in question, and our guide to the types of car keys shows why a sidewinder blade, a remote fob and a plain transponder blade are three different jobs.

Programming the car to trust the new key

With the blade turning, the transponder chip is introduced to the immobiliser — usually through the OBD port — so the ECU stores its code and allows the engine to start.

This is the part most people never see. The locksmith connects a key programmer to the car's diagnostic port and follows the manufacturer's security procedure for that model. In an all-keys-lost situation this is a full procedure rather than a quick add-a-key, and it includes an important security step: the lost keys are deleted from the car's memory, so they can no longer start it. Some cars need a security PIN released through legitimate channels before programming can begin. The electronic side is a trade of its own — what car key programming involves explains why the blade is only half the key.

New key from scratch versus a simple duplicate

An all-keys-lost key is a bigger job than a duplicate in every respect: the blade is originated from code rather than copied, the programming is a full procedure, and the ownership check is stricter. Seeing the two side by side explains the difference in cost and time:

While the kit is out, get two keys

Adding a second key during the same visit costs far less than calling the locksmith out again later — and it ends the all-keys-lost risk for good.

The expensive parts of the job — the callout, the code retrieval, the programming session — are already covered once the first key exists. A second blade and chip ride on the same session for a fraction of the effort. Drivers who decline the second key often meet us again a year later, paying full price for the same procedure. If the budget stretches, take the pair. Our post on why a spare car key is worth having makes the case in full.

Need a new key made from scratch?

If every key is gone, the fix is one conversation away. We verify ownership, cut to code and program at the car — across Alvechurch, Bromsgrove, Redditch and Birmingham South, 24 hours a day. For the full lost-keys service, see lost car keys locksmith, or call or WhatsApp 07367 634032 and we will talk you through exactly what we need from you.