Question 1

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

Accepted Answer

Yes. The 2007 LX uses a conventional ignition cylinder, so extraction is a standard job. I remove the broken piece without pulling the whole column apart. Once the fragment is out, I pull your key code from the door lock or from vehicle records and cut a new blade to spec. That matters because a worn key that finally snapped was probably already riding the tumblers wrong. You want a fresh cut, not a copy of a worn-out original.

Question 2

What exactly is a remote head key and why does my 2007 LX use one?

Accepted Answer

A remote head key is a single unit where the fob electronics are built directly into the key head rather than hanging on a separate keyring fob. Your 2007 LX uses one. The key contains a transponder chip that the vehicle's immobilizer reads every time you turn the ignition. If the chip is not recognized, the engine either won't start or starts briefly and immediately stalls. The same key also carries the 3-button remote for lock, unlock, and the third function, all in one piece.

Because the chip and the remote are in the same housing, physical damage to the key head can affect both. A cracked housing or a snapped blade is worth addressing before it leaves you stranded, not after.

Question 3

My Lexus is showing a key warning and won't respond to the fob. What should I check first?

Accepted Answer

Start with the battery. The 2007 LX remote head key runs on a CR1616, and when that cell gets low, you can get a warning light and reduced or no remote response before the key completely stops working for start functions.

If you have already replaced the battery and the warning persists, open the fob back up and check that the cell is seated flat against both contact points. The tabs inside these housings lose tension over time.

If the fob battery is confirmed good and seated correctly, hold the fob head directly against the ignition cylinder area and try to start. The transponder chip can still communicate passively even without remote battery power, so this tells you whether the immobilizer side is still reading the chip. If it starts that way, your remote circuit has an issue but the chip is fine. If it does not start that way either, bring in a tech with diagnostic equipment to read what the vehicle is seeing.

Question 4

I bought a replacement fob online. Can I program it myself at home?

Accepted Answer

Not on this one. The 2007 LX does not have a driver-accessible onboard add-a-key sequence for the remote head key. Programming the transponder chip to the immobilizer requires a professional tool connected to the vehicle. If you already have the spare key in hand, bring it to me and I can program it on site in North Park without a dealer trip. The blade still needs to be cut to your vehicle as well, so a blank fob off a parts site is only half of what you need.

Question 5

My remote works fine but the engine starts and immediately stalls. Is that a key problem?

Accepted Answer

That specific symptom, starts and dies within a second or two, points directly to the immobilizer not completing its handshake with the transponder chip. The remote functions and the transponder chip inside your remote head key are separate circuits. A key can lock and unlock your doors perfectly and still have a chip that the vehicle is not reading correctly.

It could be the chip inside the key, it could be the antenna ring around the ignition cylinder losing its read range, or it could be the immobilizer module itself. I have seen this on 2007 LX keys where the chip was damaged from a key being dropped or bent. Bring the key and the vehicle together so I can test the chip read before assuming anything needs replacing.

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