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Car Key Technology Explained

There are typically 2 elements to vehicle security – Vehicle Entry & Starting the Vehicle.

Vehicle Entry

It’s rare to have to insert a key into your vehicle these days to open the doors, as most vehicles have push button remote locking/unlocking.

Early remote systems used basic RF (radio frequency) systems which were not very secure – the signals could be captured by a third party using black electronics and then played back to gain access to the vehicle. Newer systems use a rolling code (or hopping) system. With this system the code transmitted is never the same, so recording the signal is useless to a thief. A new code is generated constantly by the remote key. The vehicle’s receiver also generates the same new code as both items use the same key number for generating the next code, so the receiver will always know what code to expect.

Ok…so what if someone presses the remote out of distance from the vehicle, surely the codes will be out of sequence and the vehicle won’t open, right? No. To counter this problem the receiver will accept the next 100 or more rolling codes generated. As the code system normally has a billion to a trillion plus permutations, allowing a few hundred variations does not compromise security.

However, if someone has been pressing the remote numerous times out of distance of the vehicle (maybe a hyper bored sales rep or kids messing around!) then the remote may stop working and fail to open the vehicle. In this case the remote can normally be sychronised again quite easily, depending on the vehicle – see our remote programming instructions.

Some manufacturers, particularly French companies like Renault and Peugeot employed infra red technology in some of their early remote locking systems. This required pointing towards the vehicle at the receiver to lock and unlock the vehicle. Most if not all infra red systems have been replaced by RF technology now. If you’ve lost a remote control for an infra-red system there’s a good chance you can easily reprogram a new or even second hand key remote to your vehicle with our instructions.

Pioneering technology doesn’t even require pressing anything for entry. Systems range from simply having the key/smart card within a certain distance of the vehicle to open or lock the doors to fingerprint recognition incorporated within the door handle.

Starting a Vehicle

The original vehicle keys were no more advanced than a standard front door key to your house. While your house can’t be driven away your car can and ignition barrel locks on vehicle’s have proved to be little defence to criminals.

With vehicles now being controlled by computers (ECU) this technology has also extended to the vehicle’s key. Most vehicles today now employ transponder technology in the key as added security.

On luxury vehicles keys can be individually coded to suit the driver. So once the key is inserted all settings such as seat position, steering wheel height, headrest and door mirrors will adjust as programmed for that driver.

There are even valet keys which only allow access to driving the vehicle but no access to the boot or glovebox where valuables may be stored and will also restrict the vehicle’s power output to avoid any abuse to the vehicle.

The latest technology being employed by manufacturers like Mercedes Benz is to remove the key altogether replacing it with fingerprint recognition.

How does a transponder chip work?

The transponder chip is a small electronic component which contains an individual electronic code. Physically they usually just look like a small piece of plastic with some writing on them of the manufacturer and part number.

Once energised they transmit this electronic code to your vehicle’s ECU. If the code is valid then the ECU will open everything up to allow the car to be started.

How are they powered to transmit? They don’t actually need a wired battery supply to them. Once inserted into the car’s lock or receptacle, a transponder ring wirelessly energises them to transmit. 

On some car key remotes you may find them once you open it up to change the battery. On solid keys they will be buried into the plastic body and not accessible.

Transponder Chip Car Security
An example of a transponder chip in a car key