Transponder keys, remote controls, remote head keys and proximity remotes…a brief synopsis

Often when a customer calls requesting a replacement key for his vehicle, I quote the price, mentioning that the price also includes programming the key, if necessary (the term, “programming the key”, is not accurate; actually I am programming the vehicle’s ECU to accept the frequency of the new key’s chip, but I will save this bit of information for a few lines down). The customer stops me short, and says, “No, this key does not have a chip. It doesn’t have any buttons or anything. This is just a regular key.” I carefully explain all the facts and nuances concerning the key, and how it does indeed have a chip, etc. etc., and I often think, “I should write an article about this. Maybe talk about what the different terms mean. That sort of thing.”

Well, here I am. I’ll try to keep it brief, not too boring, and hopefully somewhat informative.

A key to a car can be a regular metal key, or it can be a transponder key. A transponder key is a key that has a tiny chip embedded in the plastic head of the key. You cannot see it. A transponder equipped vehicle requires not only a key to turn the igniition, but the vehicle must be programmed to accept the fre3quency of the chip that the key has; if it is not programmed, the vehicle will not start. The key will turn, and nothing will happen. Nada.

A remote control is a programmed frequency transmitter that transmits a signal which can be used to lock and unlock doors, open the trunk, etc. A transponder chip has nothing to do with the remote, and vice versa.

A remote head key is a key that has the remote control in the head of the key. A transponder chip might also be embedded in the head of the key, but the two are still not related to each other. It is possible to have a remote head key for a car, but not have a transponder chip, as a particular vehicle may not require one. It is also possible to have a remote control by itself, sharing space on your keyring with your key.

A proximity remote is a remote control unit that also has a chip in it. When this unit is inside the vehicle, the engine ECU (aka “brain”) senses the presence of the unit, and allows the vehicle to be started, usually by pushing a button.

Vehicle manufacturers have made things a bit less simple than the above narrative. Remote controls and transponders are two wholly seperate things, so programming one may (or may not) program the other; oftentimes the two devices require their own distinct programming. A remote control might work on the door locks, but if the transponder is not programmed, the engine is not going to start.

Some vehicles (Toyota comes to mind), have a blinking light (the security light) that will not turn off unless a proper OEM (original equipment manufacturer) remote head key is utilized to start the car; although a standard programmed transponder key will start the car, the dash light will continue to act as though it is disabled. Additionally, many vehciles are “transponder optional,” meaning a certain vehicle may require a transponder key, while another, of the exact same type, model and year, may not.

Programming requirements can vary by vehicle, but oftentimes basic programmers can be utiized. Newer vehicles almost always require more sophisticated programming equipment, and programming can be expensive; it may even exceed the price of the key itself.