Is a Cloned Car Key Really a Second Key? Your Car May Not Agree
Short version: A copied car key can start your car just fine, but a copy isn't always a second key. If the key was cloned instead of programmed to the car, your car may still count one key. You usually find out at the worst time, after a key is lost and the car needs its keys registered again. Find out which kind you have while it's still cheap to fix.
One of the technicians we work with has watched this cause problems over and over. People think they have two keys. The car thinks they have one.
It's an easy mistake to make. You get a second key from a hardware store, a kiosk or a low-priced locksmith, it starts the car, and you'd have no reason to think about it again.
Cloned or programmed: what's the difference?
Most modern keys carry a transponder, a small chip the car reads before it lets the engine start. There are two ways to get another key that passes that check.
A programmed key goes through the car's own key registration. Key supplier Car Key Source says "The new key gets its own identity in the immobilizer." The car knows about it, and it can be removed later on its own.
A cloned key copies an existing key onto a special chip. The car is never involved. In Car Key Source's words, "nothing on the car changes and no diagnostic session is needed," and the car "still believes only the original keys exist." The trade magazine Locksmith Ledger says the vehicle "cannot distinguish one clone key from another."
That's why copies are quick and cheap. It's also why the car doesn't gain a second key.
Where copies come from
Hardware stores and kiosks
Retailers don't tend to say "clone." KeyMe says its kiosk "scans your key, including transponder (chip) data when supported," then cuts a replacement that may be ready to use right away. That sounds like a copy of your key rather than a new key added to the car, but that's our reading, not their wording. KeyMe also says some keys need "specialized programming equipment or manufacturer-specific procedures," and Minute Key says smart car keys need programming.
We're not saying don't use them. A working spare is handy. Just ask the question before you pay: will this key be programmed to my car, or is it a copy of the one I brought in?
Low-priced locksmiths and online keys
Plenty of good locksmiths program keys properly, and Toyota itself says "certain bonded/registered independent locksmiths" can make replacement keys. The trouble is the cheap job that skips the car's registration procedure, because you can't see the difference when you pick it up.
Copied chips have limits too. Locksmith Ledger says some can be "cloned once or just couple of times," and Car Key Source says newer chips are "harder or not cloneable at all." FORScan, a diagnostic program used on Fords, warns that cheap new clone keys may all share one ID, so someone who buys two or three "will be able to program only 1 of them."
Why it matters when a key is lost
When a key goes missing, the fix is usually to change what the car has stored. That's where a copy stops helping.
No automaker we read mentions clones. They only talk about registered keys, and they're strict about those. A few examples:
- Toyota: Its maintenance guide says "each vehicle should have two master keys." On a smart key reset for lost keys, its service bulletin says "all previously registered keys will be erased and can never be reused."
- Honda: When no programmed keys are left, a service bulletin says the scan tool "clears all transponder codes" and stores the replacements.
- Nissan: One owner's manual tells you to bring every key to the dealer, because "the registration process will erase the memory of all key codes previously registered."
- Subaru: Its manual says a lost key's code "still remains in the memory" of the car, and "all keys that will be used are required" to erase it.
- Chevrolet: One manual says that when a replacement is programmed, "all remaining keys must also be reprogrammed."
- Hyundai: One manual says "All keys must be present when programming a new key."
- Ford: Ford's PATS anti-theft system "identifies a key by transponder ID," according to FORScan, and after an erase the car needs two different keys. Two clones of one key look like "only 1 unique key," so the car won't run.
These come from specific manuals and bulletins, so your car may differ. Your manual will say what yours does.
Put that together and you can see two problems with a clone, though this part is our reading, because the automakers don't address clones directly.
It may not count. If a car needs two registered keys, a key and its clone may only cover one of them.
It's hard to cancel. Say you lose the clone. A clone and its original share one identity, so we don't see how a shop could remove just the lost copy. To shut it off, the original likely has to go too, and new keys get registered in its place. If the lost key was a true second key, a shop can usually remove that one by itself.
When this catches people
- You lose a key. You thought you had a spare. You have a copy, and now the car needs a new registration.
- You bought the car used. Two keys came with it, and nobody knows how they were made. FORScan says a new owner "may even have no idea that one of these keys is not genuine." Ask about keys alongside your pre-purchase inspection. Our used hybrid and EV guide covers what else to check.
- Someone erases the keys to fix a problem. Once a car's keys are erased, a pile of copies may not get you back on the road. FORScan's Ford guide calls erasing "potentially dangerous, because engine will not start until you program at least 2 keys." Don't let anyone erase keys until known-good keys are in hand.
What we'd do
- Find out what you have. If you don't know where a key came from, call whoever made it and ask whether it was cloned or programmed to the car.
- If it's a clone, or nobody knows, add a real key. Ask for a new key registered to the car. Ask them to confirm that the car now shows the number of keys you expect.
- Use the dealer or a vetted locksmith. We have a licensed and bonded Oregon locksmith on staff. Toyota also points owners to aloa.org to find a bonded or registered locksmith.
- Bring every key you own. Several automakers require it, and some will wipe what isn't there.
- Keep the clone if you like. It can still be a handy backup. Just don't count it as your spare.
All of this is cheapest while you still have a working key. Toyota's guide says "Replacing an immobilizer key may be costly."
If your car suddenly stops seeing a key at all, don't start with the key. A weak 12V battery can cause that too, and we've written about how the 12V battery causes no-starts on hybrids.
Common questions
Is a cloned key bad?
No. It starts the car, and it's useful as a backup. The problem is thinking it's a second registered key.
Can I tell a clone by looking at it?
Usually not. Ask whoever made it.
Does every hardware store key work this way?
No, and it varies by store and by car. Some services send a van that programs keys. That's why you should ask how your key will be made.
I only have one key. Should I worry?
We wouldn't panic, but we'd fix it soon. With one key, you're one lost key away from a much bigger bill.
Questions about your car? Text us at 503-969-3134 — it's the fastest way to reach us.
About the author: Travis Decker is the owner of Atomic Auto in Portland, Oregon, and an ASE Master Technician (L1, L3). Atomic Auto specializes in Toyota, hybrid, and EV service.
General information from the sources linked above. Your car is its own case, and we would rather test it than guess.
Text us, or book a slot.
A text with a photo of the dash gets you an answer fastest. Booking online holds a day and a time.