The difference comes down to whether you have to press a button. A conventional key fob is a remote: you press lock or unlock, and you still put a key in the ignition (or the remote is built into the key head). A smart key, also called a proximity or intelligent key, works passively: the car detects that the key is nearby, so you can unlock the door by touching the handle or a request button and start the engine with a push button while the key stays in your pocket or bag.

Not sure which one your car uses? Call (613) 707-4884 and we can help you identify it.

How a Traditional Key Fob Works

A remote key fob sends a coded radio signal only when you press a button. It handles convenience functions — lock, unlock, trunk and panic alarm. Starting the car is a separate job: a physical key turns the ignition, and a transponder chip in that key (or in the remote head) tells the engine immobilizer the key is genuine. Many vehicles combine everything in a "remote-head key" or a flip key, but the principle is the same: buttons for the doors, a blade and chip for the engine.

How a Smart (Proximity) Key Works

A smart key communicates with antennas in the vehicle. When the key is within a short range of a door or inside the cabin, the car recognises it and allows the doors to unlock and the push-button start to work. The passive range is deliberately small. Nissan's owner's manual, for example, gives the Intelligent Key operating range as within 80 cm of each door or tailgate request button, and notes that a discharged key battery or strong radio waves can shrink that range. The buttons on a smart key still work as a normal remote, often from much farther away.

Most smart keys also contain a hidden mechanical key for opening the driver's door if the battery dies, and push-button vehicles usually have a back-up way to start the engine with a weak key battery, such as holding the key against the start button. Your owner's manual describes the exact procedure.

Quick Comparison

  • Unlocking: key fob — press a button; smart key — touch the handle or request button with the key nearby (buttons also work).
  • Starting: key fob — insert and turn a key; smart key — press the start button with the key inside the car.
  • Battery drain: a smart key is in regular communication with the car, so its battery often needs replacing sooner than a button-only remote's.
  • Back-up: both usually include or come with a mechanical blade; smart-key vehicles also have a weak-battery start method.

Why Replacing Them Is Different

Replacing a basic remote can be fairly simple: the remote is paired to the car's receiver and, if it is a remote-head key, the blade is cut and the transponder programmed. On some older vehicles, owners can even pair a remote themselves using a procedure in the manual.

A smart key is tied more deeply into the vehicle's security system, because the same device both opens the doors and authorises the engine to start. Programming one requires diagnostic equipment that talks to the car's immobilizer or keyless-entry module, and some manufacturers restrict this with security access codes or online authorisation. The key itself is also a more complex part, and it must match the vehicle's frequency and system exactly. That is why smart-key replacement generally takes more time and costs more than a basic remote. For the push-button-specific process, see our guide to push-to-start key replacement; if the issue is a fob that has stopped responding, start with our key fob troubleshooting guide.

How to Tell Which You Have

  • If your car has a push-button start and you never take the key out of your pocket, you have a smart key.
  • If you have to insert something and turn it to start the car, you have a conventional key with a remote fob, even if the remote is built into the key head.
  • Some vehicles have a push-button start but still need the key placed in a slot or a specific spot when its battery is weak — those are smart-key systems too.

Next Step

If you need a smart key added, replaced or reprogrammed, see our smart key programming service. For help identifying your key or ordering the right one, call (613) 707-4884 with your vehicle's make, model and year.