Question 1

What is the cheapest way to replace my 2017 CX-3 key?

Accepted Answer

Call a mobile locksmith before you call the dealer. Dealer pricing on a smart key replacement for this generation CX-3 tends to land well into the several-hundred-dollar range once you factor in the fob, the programming labor, and often a tow if you have no working key at all. That does not count the appointment wait.

With EZ Car Keyz, the job comes to you. You are not paying for a tow, you are not sitting in a dealership waiting room, and the pricing is a fraction of what the dealer route costs. Call for a quote specific to your situation, because whether you have a working key to copy or you are starting from scratch makes a real difference in scope.

Question 2

How much more does all-keys-lost cost versus adding a spare?

Accepted Answer

Meaningfully more, and not just in price. When you have a working key, adding a spare is a programming job. The existing key is already registered, the system is active, and we are adding to it.

When all keys are lost on the 2017 CX-3, the vehicle security system requires a full reset before it will accept any new fob. On some Mazda smart key setups, the initialization sequence also requires two fobs to complete before either one is recognized. That means more time, more parts, and more complexity.

The honest advice is to get a spare made now. If you have one working fob in hand, the job is simpler and cheaper. Waiting until that last fob is gone is the most expensive version of this problem.

Question 3

Are aftermarket CX-3 fobs cheaper and do they actually work?

Accepted Answer

Cheaper upfront, mixed results in practice. Some owners have bought aftermarket fobs, had them programmed, and reported no issues for a year or two. Others have had a generic fob fail within days or trigger a persistent key warning in the dash that would not clear even after the fob was removed from the system.

Mazda's immobilizer is selective about what it accepts. A fob that programs cleanly on the first session can still cause communication issues down the road if the internal components are not built to the same tolerance as the factory unit.

We carry fobs built to OEM specification for this vehicle. That means the transponder chip, the RF section, and the housing contact points are all matched to what the system expects. You are not gambling on whether it works at three in the morning in a parking lot.

Question 4

My CX-3 started fine yesterday. Today it shows a key warning and will not start. Nothing changed. What happened?

Accepted Answer

This is one of the more common calls I get on this generation. The fob battery on the 2017 CX-3 uses a CR2025 cell. When it drops below the threshold the vehicle's receiver needs, the car stops recognizing the fob entirely, and a key-not-detected type warning shows at startup. It can happen fast, sometimes overnight, especially in cold mornings or if the fob has been sitting in a pocket next to other electronics.

First move: replace the battery with a CR2025, specifically that size, and make sure it is seated flat and making full contact on both terminals. If the warning clears and the car starts, that was it.

If a fresh correct battery does not fix it, the fob itself may need attention or the vehicle's receiver may have a separate issue. That is when you call.

Question 5

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

Accepted Answer

You need a technician with diagnostic equipment. The 2017 CX-3 smart key system does not have an onboard self-programming sequence. There is no ignition-turn trick, no button combination, no DIY method. Registration happens through the OBD port using professional software.

If you already bought the fob, that is fine. Bring it, or have it ready when I arrive. I can program a customer-supplied fob as long as it is the correct unit for this vehicle. What I cannot do is guarantee the fob itself if it turns out to be a non-compatible aftermarket unit. That is the one risk you take buying online before confirming compatibility.

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