Lost Your Only Car Key? What Happens Next

The first ten minutes

• Retrace your steps and call the last places you were. Keys handed in at a store or a gym are more common than people think.
• Check whether the car is locked. If it is unlocked and the key might be inside, look under the seats and in the door pockets before anything else.
• Find the paperwork: your ID and the registration or title. Registration is often in the glove box, so if the car is locked, a photo on your phone or the DMV record helps.
• Note the year, make and model, and if you can see it, the VIN through the windshield. That is what a locksmith needs to quote.

How a key is made with no key to copy

A car key has two parts. The blade is cut to match the locks, and it can be cut from the vehicle's key code or by reading the door lock, on a code machine that handles both ordinary edge-cut blades and laser-cut sidewinder blades. The chip in the head is then programmed to the car's immobilizer, the part that decides whether the engine starts. Without that programming, a perfectly cut key opens the door and does nothing else.

With every key gone, the car has to be put into a mode that accepts a new one. Some makes build in a security wait before they allow it, which is the car protecting itself against theft, not the locksmith being slow. A few recent models only program at the dealer; tell the locksmith the year, make and model first and a good one tells you straight away whether yours is one of them.

Switch off the lost key

While the car is connected for programming, the old key can be deleted from its memory. After that, whoever finds it can open the door with the blade on some cars but cannot start the engine. If the key was lost with your address, or stolen, ask for this. It is also worth making a second key in the same visit: a spare made now is far simpler than repeating this whole process later.

Locksmith or dealer?

The dealer can do it too, but the car has to get there, which without a key usually means a tow, and then it waits for a key to be ordered and programmed. A mobile locksmith does the cutting and programming where the car is parked. The trade-off is that for a handful of models the dealer is the only route, which is exactly why the first question should be the year, make and model.

Our car key replacement service makes keys from the car itself across the Santa Clarita and San Fernando Valleys and out to Ventura County. For how chips and fobs work, see chip keys and fobs explained.

Questions people ask