Question 1

Are you licensed and insured to work on Cadillac vehicles?

Accepted Answer

Yes. EZ Car Keyz holds a California Bureau of Security and Investigative Services license, LCO#6792, and carries full liability insurance. For the 2003 Seville specifically, the work involves cutting a key to your vehicle and programming the transponder to communicate with the immobilizer. That requires both the right cutting equipment and the right programming tools. Not every locksmith who shows up with a generic key machine has the GM coverage needed for this generation. When you call, ask any locksmith whether they have specific experience with early-2000s GM transponder systems. The answer tells you a lot.

Question 2

How do I know you are not a scam locksmith?

Accepted Answer

Scam locksmiths prey on distressed situations, and a Cadillac stranded near the Santa Barbara waterfront is exactly the kind of call they chase. The pattern is consistent: low number quoted on the phone, different number once they arrive, vague explanations for why it costs more. Some will tell you a luxury vehicle needs a "special procedure" to justify doubling the price after they show up.

Here is what a legitimate locksmith does: gives you a real estimate for your specific vehicle over the phone, explains what the job actually involves, and has a verifiable business name with reviews you can read before they arrive. EZ Car Keyz has over 100,000 followers across YouTube and TikTok where you can watch the actual work being done on real vehicles. That transparency is the point. If a locksmith won't explain what they're doing or why it costs what it costs, that is your signal.

Question 3

Will the replacement key work exactly like the original?

Accepted Answer

Yes. The 2003 Seville uses a transponder turn-key, so the replacement is a metal key cut to your vehicle with a chip inside the head that registers to your immobilizer. Once it's programmed, it starts the car the same way the original did. There are no remote functions on this key because it was not designed with any. What I test before I leave is simple: the key turns the ignition, the engine starts, and the security light does not stay on after startup. If it does, the programming is not done. I don't hand you the key until all of that checks out.

Question 4

My 2003 Seville cranks but won't start and the security light is on. Is that the key or something else?

Accepted Answer

That pattern, cranks but no start with the security light illuminated, points directly at the immobilizer not recognizing the key. On this generation, it usually means one of three things: the transponder chip inside the key head has failed, the antenna ring around the ignition cylinder is damaged or has a wiring issue, or the key was never properly programmed in the first place.

The way to sort it out is to test with a known-good key first. If the car starts fine with another key, the chip in your key is the problem. If no key works, you're looking at the antenna ring or the immobilizer module itself. Both are diagnosable on-site. The cranks-but-won't-fire symptom on these is almost never a coincidence, and chasing fuel or ignition components before confirming the transponder is working is a way to waste money.

Question 5

Can I use the onboard relearn procedure to add a new key myself on a 2003 Seville?

Accepted Answer

Only if you already have a working programmed key. GM's onboard add-a-key procedure on this generation requires you to start with a functional key first, then follow a timed ignition sequence to register the new one. If you have one good key and want a spare, that process can work without any external tools.

All-keys-lost is a different story. No working key means no onboard relearn. You need a programmer and someone who knows how to use it on this specific platform. That is not a DIY situation.

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