Transponder keys, explained

Since the late 1990s most cars have a small chip in the key head. The car reads it before it lets the engine run.

Why a hardware-store copy fails

The blade can be cut to match, so the door opens. Without a chip the car recognises, the engine turns over and stops, or won't crank at all.

What a working spare needs

A key cut to the lock and a chip programmed to the car. Some chips can be cloned from an existing key; others must be added to the car's memory.

Getting one made

A mobile locksmith can cut and program the spare at the car. See our transponder key service in Fort Collins.