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As the number of vehicles equipped with remotes increased, more complexity was needed, not only to accommodate the number of vehicles, but also to provide better security. We’ve all gotten that e-mail about how thieves supposedly could “capture” the signal from your remote and use that captured signal to unlock your car. While some such devices actually do exist, their use is pretty much confined to the early fixed-code systems. Modern systems are specifically designed to prevent that kind of attack.
The first generation of advanced remotes used a “Rolling Code” system, where each remote was programmed with a series of different codes for each operation. As the remote was used, it would cycle through these different codes in a sequence that the vehicle would recognize as valid.
Important: This type of system has inherent problems if one remote is used regularly while another is used only occasionally. The remote that is rarely used may get out of sync with the vehicle and no longer operate. The owner’s manual of the vehicle usually includes a warning and instructions on how to “resynchronize” the remotes.
The current generation of advanced remotes uses an “Encryption” system similar to that used by transponders located in vehicle keys. Both the remote and the vehicle are programmed with a mathematical “algorithm” that allows the remote and the vehicle to communicate. The signal sent between the remote and the vehicle is extremely complex and changes constantly. This Encryption system provides a very high level of security, eliminating the possibility of thieves using a captured signal, since the information changes every time the remote is used.
Just as the remotes have become more complex, so have the programming procedures. Just as with transponder equipped keys, there are basically two types of programming - on-board-programming and programming that requires the use of a diagnostic device. As a general rule, older vehicles will use on-board programming and programming via a diagnostic machine is generally used on the newer vehicles that use rolling codes or encryption. But some older vehicles will require a diagnostic device and some new vehicles can be programmed with on-board methods.
There is one rule that you can count on most of the time, and that is that most vehicles, new and old, use what is called “all at once programming.” Any time you put the vehicle into the programming mode, all of the currently programmed remotes are erased from the vehicle’s memory. All of the remotes, both old and new, must then be programmed back into the vehicle. This process is sometimes referred to as “re-initialization.”
On-board programming can vary greatly from one vehicle to another and makes use of controls that are built into the vehicle such as the key-minder switch in the ignition, door logic switches in the individual doors and trunk, brake pedal switch, etc. Sometimes jumper wires are used to temporarily connect two or more circuits, usually through the On-Board Diagnostic port (OBD). Here are two examples of typical on-board programming procedures.
1995 Nissan 300ZX
Photo 2 shows a 1995 Nissan 300ZX that is my personal vehicle, and yes it has been thorough a hurricane – two in fact – and a tree fell on it during hurricane Ivan. As you can see in photo 3, I have also completely worn out the plastic bail that is used to attach the remote to my keychain, so the original remote will no longer stay on the keychain. This is a common problem.
Photo 3 also shows the two new remotes that I’m going to program into my car. This car uses a fixed-code system and the remotes can be cloned. (I’ll cover the cloning procedure later.) The KeylessRide remote shown on the right was ordered over the Internet already programmed with the information necessary to operate on Nissan 300ZX vehicles made in 1994 and 1995. The second remote is a generic cloneable remote that operates on the same frequency as the original remote. For the purposes of this article, I cloned the functions from my original remote into the generic remote only.
As soon as I cloned the original remote into the generic remote, it would operate my vehicle just like the original OEM remote. This gave me two compatible remotes, only one of which is programmed into my vehicle. Because of the all at once programming, in order to add the second remote, I will need to perform the on-board programming procedure with both new remotes. This programming will erase all of the existing remotes from the vehicle memory and then program the two new remotes into the vehicle.