Question 1

My key broke in the ignition. Can you get it out?

Accepted Answer

Yes, and on the 2009 MKX it is a manageable extraction job. The ignition cylinder on this generation is accessible, and I use a hook-style extractor to catch the broken blade and pull it free without damaging the cylinder walls or the wafers inside.

Once the broken piece is out, I can cut a new blade to your vehicle right there on site, either from the key code on file or by decoding the lock directly. If the cylinder has been binding or sticking before the key broke, that is worth diagnosing at the same time, because a worn cylinder can chew up a new key just as fast. Most of the time though, extraction plus a new cut is all it takes and the car drives away the same day.

Question 2

What exactly is a remote head key and what makes it different from a regular key?

Accepted Answer

A remote head key is a single unit where the key blade and the fob are built together rather than being separate pieces. Your 2009 MKX uses one. The fob portion handles your lock, unlock, and other remote functions. The blade portion has a transponder chip embedded in it that the immobilizer reads every time you turn the ignition. If the chip is not recognized, the engine will not run, or it will start and cut out within a second or two.

That combined design means if the fob side stops working, you can still start the car with the blade. But if the transponder chip is damaged or was programmed incorrectly, the fob buttons might work fine while the car refuses to start. They are two separate functions sharing one housing.

When a remote head key gets cracked or the blade snaps at the collar, the chip inside sometimes survives intact. Depending on the damage, the chip can occasionally be transferred to a new shell, but a full replacement with fresh programming is the more reliable path and what I usually recommend.

Question 3

My 2009 MKX is showing a key-not-detected warning. Where do I start?

Accepted Answer

Start with the CR2032 battery in the fob. A cell that is on its way out will cause intermittent detection failures before it dies completely, and the symptom often looks worse than it is.

If the battery is fresh and you are still getting the warning, try holding the fob closer to the ignition cylinder when you turn the key. Passive read range drops when the battery is weak or the chip is having trouble, and proximity can bridge the gap temporarily while you sort out what is actually going on.

If neither of those changes anything, the next thing to check is whether the main vehicle battery is holding a solid charge. A low main battery can confuse the security modules and produce false key rejection warnings that have nothing to do with the fob itself. Owners on Lincoln forums have reported this exact pattern after the car sat for an extended period: both fobs rejected, fresh fob batteries made no difference, and a full power reset after charging the main battery brought everything back to normal.

If you have been through all of that and the warning persists, that is when you need a technician with the right diagnostic equipment to read what the security system is actually seeing.

Question 4

I bought a replacement fob online. Can I program it myself or do I need a tech?

Accepted Answer

You need a tech. The 2009 MKX does not have an onboard self-programming sequence for adding remote head keys. Programming requires a professional scan tool connected to the OBD port to write the new key into the immobilizer. There is no ignition-turn trick or button sequence that handles this on your generation of vehicle.

The fob you bought online is likely a valid starting point, assuming it carries the correct factory FCC ID for your vehicle. But uncut and unprogrammed, it will not start the car and the remotes will not work. Bring it when you call and I can usually cut and program it on site, which saves you the cost of the hardware at least.

Question 5

How many keys can the 2009 MKX hold in its system, and does adding a second key erase the first?

Accepted Answer

The immobilizer on this generation can hold multiple programmed keys. Adding a second key does not erase the first one, provided you use the correct add-a-key procedure rather than an all-keys-lost reset.

The all-keys-lost procedure is a different process used when no working keys exist at all. That one does wipe the existing key memory before writing new keys in, which is why it matters that a technician knows which situation they are actually dealing with before they start. If you hand someone a working key and they run an all-keys-lost reset anyway, your original key stops working the moment the new one is written. I have seen that happen when owners brought a previously programmed key back to a shop that did not confirm what was already in the system.

If you want a backup key, bring your current working key with you. That keeps things simple and keeps your original key active.

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