Question 1

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

Accepted Answer

Three things to check before anyone touches your G20. First, ask for a firm price for a 2002 Infiniti transponder key on the phone, including programming. A real tech knows what this job involves and can quote it. Vague answers like "depends when I get there" are a stall.

Second, when they arrive, ask what tool they're using to program the key and how they access the immobilizer on this car. A legitimate locksmith can explain the process in plain terms. Someone who stumbles on that question or says they'll figure it out on site is not prepared for this job.

Third, watch for an unmarked vehicle and no business ID. Not a dealbreaker on its own, but combine it with the other two and you have your answer. The G20 transponder system is not exotic, but it does require the right equipment and the right procedure. Not every locksmith carries what's needed.

Question 2

What is a transponder key and why does my 2002 G20 need one?

Accepted Answer

The key has a small chip embedded in the plastic head. When you insert it and turn the ignition, the car reads that chip. If it matches what the immobilizer has on record, the engine starts. If the chip is missing, damaged, or not programmed, the car will crank but not fire, or in some cases won't crank at all.

This is not a remote or a fob. There are no buttons, no battery, nothing to replace on the key itself. The chip is passive, meaning it draws power from the car's reader coil, not its own source. A correctly cut key with no programming looks identical to a programmed one, which is why a hardware store copy will crank the engine but not start it.

Question 3

What equipment do you use to program a key for the 2002 G20?

Accepted Answer

For this car, I work through the OBD port using a professional key programmer that supports the Infiniti immobilizer protocol for this generation. The process involves reading the vehicle's security data, then enrolling the new transponder chip so the immobilizer recognizes it as authorized.

The 2002 G20 is old enough that the immobilizer platform is well-documented and the programming procedure is reliable with the right tool. This is not a vehicle that needs dealer-level factory software access or any kind of secure gateway login. What matters is having a programmer with solid Infiniti coverage for early 2000s vehicles and knowing the correct procedure for this specific generation. I've done enough of these that the programming step is the routine part of the job.

Question 4

I bought a replacement key blank online. Can you just program it, or does the cut matter too?

Accepted Answer

Both matter. The blade has to be cut to your specific vehicle, either from your existing key, from a key code on record, or by decoding one of your locks. If the cut is wrong, the key won't turn the cylinder regardless of whether the chip is programmed correctly.

The chip side also has to be right. Not every blank sold online carries a compatible transponder chip for this car, even if the listing claims it fits a 2002 G20. If the chip type is wrong, programming will either fail outright or appear to succeed but the immobilizer will still reject it at start.

Bring the blank if you have it. I'll tell you on the spot whether it's usable. If it's not, I carry stock that I know works with this system.

Question 5

My 2002 G20 cranks but won't start. Could this be a key or immobilizer problem?

Accepted Answer

It can be, and the G20 does show up in owner forums with this complaint. The typical sign that the immobilizer is involved is a security warning light staying on or flashing on the dash after you turn the key. If that light comes on and stays on, the car has flagged the key as unrecognized.

That said, a crank-no-start has a long list of possible causes that have nothing to do with the key. Fuel, spark, crank sensor, and ignition switch problems all produce the same symptom. The immobilizer is one item on that list, not the automatic answer.

If the security light is behaving normally and the car still won't start, the key system is probably not the issue. If the light is abnormal, that's where I'd start looking.

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