Question 1

How do I spot a fake locksmith before I get ripped off?

Accepted Answer

A few things to watch for specifically if you're calling about a Cadillac. If they can't give you a real estimate for your specific year and model over the phone, that's a problem. If the quote is an unusually low "service call" rate with a promise to sort out the rest on arrival, that's a bait-and-switch setup. One CT4 owner posted on a GM forum about calling a "local" number that routed to a call center, and the van that showed up had no markings and the tech didn't know what programming equipment the job required.

A real locksmith who works on GM push-to-start vehicles should be able to tell you, without hesitating, what the process looks like for your car, what tools are involved, and approximately how long it takes. If they stall or get vague, move on. Search their business name and look for a real address, real reviews, and some evidence they've worked on GM vehicles before. Cadillac key work is not the same as cutting a house key.

Question 2

What exactly is a remote key and why can't I just copy it somewhere?

Accepted Answer

The key your 2020 CT4 uses is a key fob with a built-in transponder chip. The transponder has to be paired to your vehicle's immobilizer through professional diagnostic equipment. Without that pairing, the fob can unlock the doors but the car will not start. There is no hardware store in Poway, or anywhere, that can copy the programming side of this. The physical emergency blade inside the fob can be cut to match, but the electronic piece is the part that takes a tech with the right tools.

Question 3

What equipment do you use to program Cadillac keys?

Accepted Answer

For the 2020 CT4 specifically, I use professional-grade diagnostic tools that support GM's current immobilizer protocols and security access requirements. The process involves getting into the vehicle's security system through the OBD port, completing a timed access window, and registering the new fob. On GM's newer push-to-start platforms, there's a mandatory wait built into the security access sequence. You can't skip it. Tools that aren't running current firmware will fail that step, and the job doesn't complete.

I keep my equipment updated because GM has rolled out protocol changes across model years. A tool that worked on a 2018 GM vehicle isn't automatically ready for a 2020 without current firmware. That's a real failure point I've seen other techs run into. If a locksmith shows up and their tool throws an unsupported protocol error, you're waiting while they troubleshoot, or they're leaving without finishing.

Question 4

Can I buy a replacement fob online and just have someone program it, or does it have to come from the dealer?

Accepted Answer

You can buy an aftermarket or salvage fob with the correct factory FCC ID for your car and have it programmed. The fob doesn't have to come from the dealer. What matters is that the fob matches your vehicle's system. A fob with a mismatched configuration won't pair correctly even if it looks identical on the outside.

The programming itself has to be done by a tech with the right equipment regardless of where the fob comes from. Buying the part online and paying for programming separately is a common way owners save money compared to the dealer supplying everything. Just confirm the part matches before you buy it, or let me source it. I'd rather verify it upfront than show up to find the wrong fob in hand.

Question 5

My CT4 is showing a key warning on the dash even though the fob has a fresh battery. What's going on?

Accepted Answer

Fresh battery rules out the obvious, but it doesn't rule out everything. A few things come up on these cars. First, CR2450 specifically, not a CR2032, not a CR2016. Wrong battery fits but reads weak. Second, the contact inside the fob can corrode or bend slightly, especially if the battery was replaced by prying instead of sliding. The cell might be making intermittent contact and the car is catching the drop.

If the battery and contacts check out and the warning is still there, the fob's transponder may have lost its pairing. That's less common but it happens, usually after a battery went fully dead for an extended stretch. At that point the fob needs to be re-enrolled, which takes a diagnostic tool. It's not a hardware store fix, but it's also not a half-day dealer visit.

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