What car makers have fixed — and what Leighton Buzzard drivers still need

It is a fair question, and one Leighton Buzzard drivers ask with a certain amount of scepticism: if relay theft has been well understood for years, why have the manufacturers not simply fixed it? The honest answer is that several of them have made real progress. It just does not help most of the people asking.

The first improvement was the motion-sensing fob. The key contains a small accelerometer, and if it has been still for a few minutes it stops broadcasting until it is picked up again. A fob asleep on a hall table cannot answer a relay device, because it is not answering anything. It is a genuinely good idea, it costs the manufacturer almost nothing, and it works.

The second is a change in how the car and key measure distance. Older keyless systems ask only whether a valid key is responding, which is precisely the question a relay can answer dishonestly. Newer systems using ultra-wideband radio measure how long the signal actually takes to travel, and a relay adds delay it cannot remove. A car that measures time rather than merely presence can tell that the key is not really beside it.

So the technology exists and it works. Here is why it is not the end of the conversation.

It arrived late, and it arrived unevenly. A motion-sensing fob helps only if your car came with one, and cars sold before it became common cannot be retrofitted with the feature. It is also not universal even now — it depends on the manufacturer, the model and often the trim. Ultra-wideband is newer still and is largely on premium and recent vehicles. If you are driving something from the middle of the last decade, which is most people, neither of these is on your car and neither is coming to it.

A motion-sensing fob also has a gap that is easy to overlook. It stops broadcasting when it is still — so it protects the key on the hall table overnight and does nothing for the one in a coat pocket that has just been moved, or the one in a bag on the passenger seat. It reduces the window rather than closing it.

And then the part nobody advertises: none of this touches the diagnostic socket. Every improvement described above is about making the radio conversation harder to fake. A device plugged into the footwell that programs a fresh key does not have that conversation at all. It is a different route into the same car, it works on plenty of new vehicles as well as old ones, and the fob in your pocket being clever about accelerometers is irrelevant to it.

There is also a straightforward commercial reality. A manufacturer is designing for convenience first, because that is what sells cars — the entire point of keyless entry is that you never take the key out. Security measures that make the system occasionally hesitant are unpopular in showrooms, and the incentive to be first with a stricter system is not strong.

None of which means you should be cynical about it. If you are buying a new car, ask whether the fob sleeps and whether the system uses ultra-wideband, because on a new purchase it is a reasonable thing to weigh. What it does not do is help the car currently on your driveway.

For that, the approach that does not depend on the manufacturer is to make the key insufficient by itself. A Ghost II or a CAN Phantom sits on the car's own data network and will not let the engine fire until a sequence you chose is entered. It works the same on a 2014 car as on a 2025 one, and it is indifferent to whether the key was relayed, cloned or programmed through the socket in the footwell. Send us the registration and we will tell you what your car already has and what it still needs. We fit across Leighton Buzzard, Linslade and the LU7 villages.