Infiniti G35, G37 and Q40 Spare Intelligent Key (2007-2015): Plano Guide

The Infiniti G sedan and coupe are the kind of cars people keep. Plenty of them around Plano are on their second or third owner, and a large share of those changed hands with a single key in the envelope. That one oval fob has now been opening and starting the car for more than a decade. If it is the only one you have, this guide covers which key your car takes, what a spare costs, and why the best time to make one is while the first key still works. For a spare made at your home or office, call or text (945) 307-3827.

Quick Answer

As of October 2026, a spare Intelligent Key for an Infiniti G35, G37 or Q40 in Plano typically runs $250 to $480, cut and programmed on site with one working key present, in about 30 to 60 minutes. A second spare in the same visit adds $110 to $260. The same key after every key is lost runs $380 to $700 or more. Every key you want to keep must be at the appointment, because the car re-registers its whole key set in one session.

Which Key Does Your G Take?

The G line changed its key system partway through its life, and it also changed its name. Use this to place your car.

Model and years	Start type	Key
G35 sedan through 2006, G35 coupe through 2007	Turn-key on most trims	Bladed transponder key with a separate or built-in remote
G35 sedan 2007-2008	Push-button	Intelligent Key
G37 coupe 2008-2013, G37 sedan 2009-2013, G37 convertible 2009-2013	Push-button	Intelligent Key
Q60 coupe and convertible 2014-2015	Push-button	Intelligent Key, same family as the G37
Q40 sedan 2015	Push-button	Intelligent Key, same family as the G37

Two notes on that table. Some later first-generation G35 trims were offered with an early Intelligent Key and a twist knob in place of a key slot, so if your older G35 has a knob you turn without inserting anything, it belongs with the push-button group. And the 2014-2015 Q60 and the 2015 Q40 are the G37 coupe and sedan under new names. They are not related to the redesigned Q50 and later Q60, which use a different key.

Spare Key Pricing in Plano

Service	Typical Plano range (Oct 2026)	On-site time	Notes
Intelligent Key spare, one key working	$250 - $480	30 - 60 min	The standard G37 and Q40 job
Second spare added during the same visit	$110 - $260	+15 - 25 min	Mostly the cost of the part
Bladed transponder spare, early G35	$120 - $280	20 - 45 min	Turn-key trims
Fob shell or emergency blade replacement	$70 - $160	15 - 35 min	When the circuit board is healthy
Emergency blade cut only, door access	$90 - $180	20 - 40 min	Opens the door, will not start the car
Fob battery replaced and function checked	$10 - $180	10 - 30 min	Frequently the entire fix
Diagnosis when the fault may not be the key	$75 - $140	20 - 35 min	Applied to the repair if you proceed
All Intelligent Keys lost	$380 - $700+	60 - 150 min	The price a spare protects you from
After-hours or emergency response	Surcharge applies	-	Confirmed on the phone before dispatch

How the G's Intelligent Key Works

The oval fob does three jobs at once. It is a remote, with buttons for lock, unlock, trunk and panic. It is a proximity key, which lets you unlock by pressing the small button on the door handle and start the car with the fob in your pocket. And it carries a transponder that the car can read directly when the fob's battery is flat.

That last function has its own hardware in these cars. To the left of the steering column, low on the dash, there is a slot sized for the fob. With a dead fob battery, you push the fob into that slot and the car reads it at point-blank range, then starts normally. Many owners have never noticed the slot. It is worth finding before you need it.

Inside the fob is a small mechanical key, released by a catch on the back. It opens the driver's door when the fob or the car battery is dead. When a spare is made, that blade is cut to your car's lock as part of the job.

Why Look-Alike Fobs Do Not Interchange

Nissan and Infiniti used the same oval shell across many models and many years, and fobs that look identical on the outside can be different inside. They differ in the radio frequency and identification they use, in the button layout between sedan and coupe, and in whether they suit a car with or without certain options.

The identifier that matters is printed on the back of the fob or inside the battery compartment. A fob with the wrong one will not program, no matter how closely the shell matches. This is the most common reason an online fob purchase goes wrong on a G. If you plan to supply your own fob, read us those markings from your working fob first, and we will tell you whether the one you are looking at is a match. Our article on duplicate versus new programmed car keys explains the wider picture.

The All-Keys-Present Rule

This is the part of a Nissan or Infiniti key job that catches people out. Adding a key on these cars is not an addition. The session clears the stored list and registers the full set again: the key you already have and the new one, one after the other.

Two things follow from that:

• Bring every key. A working fob left on the kitchen counter will not start the car after the session until it is registered in a later visit.
• A lost key stops working. If one of your original fobs disappeared years ago, it is removed from the list when the set is registered again. That is a small security benefit that comes free with the spare.

The car stores a limited number of keys, typically up to four, which is more than most households need.

The Security PIN Step

Before the car will accept any new key, the programming equipment has to pass a security check tied to the body control module. On these model years that step is well understood and usually quick, which is one reason a G37 spare is a contained job compared with newer Infinitis. More on how that system fits together is in our guide to the Nissan and Infiniti Intelligent Key and BCM.

Why These Cars Deserve a Spare Now

The only fob is old

A fob that has been carried daily since 2010 has a worn shell, tired button contacts and a battery clip that has been bent a few times. Fobs at this age fail without much warning. When the only key fails, a spare job becomes an all-keys-lost job, and the price roughly doubles.

The buttons often fail before the key does

A very common pattern on the G: the car still starts, but the lock and unlock buttons have stopped responding. The proximity and transponder side of the fob is alive while the button side is worn out. That is a warning, not a stable condition. Our guide to a key that starts the car while the lock buttons are dead covers what is happening inside the fob.

One key means no margin

With two keys, a failed fob is an errand. With one, it is a car that cannot move until a technician arrives. If you lose the only key, the job is the one described in our page on a lost car key with no spare.

Is It the Key, or Is It the Car?

Before buying a spare to fix a problem, make sure the key is actually the problem. A few G-specific checks:

• Fob not detected, but the car starts with the fob in the slot. The fob battery is weak. Replace the coin cell first. If batteries keep dying fast, see our article on a car key battery that dies quickly.
• Car does not respond even with the fob in the slot, and a key-shaped warning light is on. These model years are known for electronic steering lock problems, where the car refuses to power up even though the key is fine. A new key does not fix that. It is a module-side repair, and our Nissan and Infiniti module programming cost guide covers that territory.
• Buttons dead, proximity fine. Usually worn button contacts or a cracked solder joint in the fob. A new fob solves it, and it is a good reason to make the spare now.
• Everything intermittent, worse on cold mornings. Check the car's 12-volt battery before anything else.

If you are unsure, diagnosis is $75 to $140 and is applied to whatever repair follows.

What to Bring to the Appointment

• Every key you have, working or not.
• Proof of ownership such as your registration or title, plus a photo ID.
• The VIN, if you want us to confirm the fob and stock before we drive out.
• The car, parked where we can open both front doors, with a battery healthy enough to hold voltage for the session. If the battery is weak, tell us and we will bring support for it.

What It Looks Like on the Day

1. We confirm ownership and identify the correct fob from your VIN and your existing key.
2. The emergency blade is cut to your door lock and tested in the door.
3. Battery support is connected, and the programming equipment is connected at the diagnostic port.
4. The security step is completed, and the key set is registered: your existing key and the new one.
5. Every function is tested on every key - door handle button, lock, unlock, trunk, panic, start from the pocket, and start from the slot.
6. You leave with two keys that both do everything.

The whole visit is usually under an hour. It happens in your driveway, at your office, or anywhere in Plano the car happens to be. For a general overview of fob work, see our page on key fob replacement in Plano or our key fob programming service page. Owners of the larger Infinitis will find their models in our guide to QX80 and Q70 Intelligent Keys.

Frequently Asked Questions

How much is a spare key for an Infiniti G37 in Plano?

As of October 2026, a spare Intelligent Key for a G37 typically runs $250 to $480, cut and programmed on site with one working key present. A second spare added in the same visit is $110 to $260.

Can I program an Infiniti G35 or G37 key myself?

Not the push-button Intelligent Key. Registration requires programming equipment and a security step tied to the body control module. There is no owner procedure for adding a proximity key on these cars.

Will a used or online Infiniti fob work on my G37?

Only if its identification markings match your original exactly, and only if it is in a condition that can be registered. Fobs that look identical are often different inside. Read us the markings from your working fob before you buy.

Do I need to bring all my keys to the appointment?

Yes. The car re-registers its full key set in one session, so any key not present will stop starting the car until it is registered again.

Is the Infiniti Q40 key the same as the G37 key?

The 2015 Q40 is the G37 sedan under a new name, and it uses the same family of Intelligent Key. The exact fob still has to match your car's identification markings. It is not the same key as the redesigned Q50.

What if my G37 will not start even with the key in the slot?

Then the key may not be the problem. These model years are known for electronic steering lock faults that prevent the car from powering up. Have it diagnosed before buying a key.

Make the Spare While the First Key Still Works

If your G35, G37, Q40 or G-based Q60 is down to one key anywhere in Plano, Frisco, McKinney, Allen, Richardson or Garland, call or text (945) 307-3827. Have the VIN and your working key handy, and we will confirm the fob before we drive out.

---

Written by the Plano Locksmith Automotive Locksmith Team - mobile automotive key cutting, programming and immobilizer work across Plano and Collin County.