2015 GMC Sierra 1500 Key Fob Programming Guide

As an ASE-certified electrical technician and automotive locksmith, I see a lot of modern GM trucks roll into the shop. The 2015 GMC Sierra 1500 is a fantastic workhorse, but losing a key fob—or dealing with a dead one—can bring your day to a grinding halt. GM made the transition to high-security "flip keys" for this generation, integrating the remote and the transponder key into a single unit.

Here is everything you need to know about replacing, programming, and maintaining the key fob for your 2015 GMC Sierra 1500.

Quick reference

Step-by-step on-board programming

If you have a standard ignition (turn-key) and you already possess one fully functional, programmed key, you are in luck. GM allows you to add a new key using a simple on-board procedure. This process will program both the immobilizer transponder and the remote keyless entry buttons simultaneously.

Note: The new replacement key must be cut to match your ignition cylinder by a locksmith or dealer before you can perform this procedure.

1. Insert your original, working key into the ignition.
2. Turn the ignition to the ON position (do not crank the engine).
3. Wait for the security light on the dashboard to turn off. (This usually takes about 3 to 5 seconds).
4. Turn the ignition OFF and remove the working key.
5. Within 10 seconds, insert the newly cut, unprogrammed key into the ignition.
6. Turn the ignition to the ON position (again, do not start the engine).
7. Watch the security light. It should illuminate and then turn off after a few seconds.
8. Turn the ignition OFF.
9. Test the new key. Start the vehicle to ensure the immobilizer accepts it, then turn it off and test the lock/unlock buttons on the remote.

If you have a push-to-start model (less common for the 2015 Sierra but available on high trims), the vehicle generally requires a diagnostic scan tool to program a new proximity fob.

Battery replacement

When your remote starts losing range or the truck displays a "Replace Battery in Remote Key" message, it's time for a new CR2032 battery.

1. Flip the metal key blade out.
2. Look inside the key cavity for a small notch or seam splitting the two halves of the plastic shell.
3. Insert a flathead screwdriver or plastic trim tool into the seam and gently pry the casing apart.
4. Remove the old battery and insert the new CR2032 battery with the positive (+) side facing up.
5. Snap the two halves of the shell firmly back together.

Where to buy a replacement fob

When sourcing a replacement flip key for your 2015 GMC Sierra, you have three main avenues:

• The Dealership: The safest but most expensive route. An OEM key will run you $150–$250, plus an additional $100–$150 for cutting and programming. Total expectation: $250–$400.
• Automotive Locksmith: A mobile locksmith can supply an OEM or high-quality aftermarket fob, cut it on-site, and program it. This usually costs between $150 and $250 total.
• Amazon / Online Retailers: The cheapest upfront option ($20–$50 for an aftermarket fob). However, you still need to find a locksmith to laser-cut the HU100 blade, which generally costs $35–$75. Beware of ultra-cheap knockoffs, as their circuit boards frequently fail.

If on-board programming isn't supported

If you have lost all your working keys, the DIY on-board programming method will not work. The 2015 GMC Sierra utilizes a strict GM immobilizer system (often using a Philips ID46 transponder chip) to prevent theft.

In an "all keys lost" situation, the vehicle's computer must be reset to accept new keys. This cannot be done with a button dance. You will need a professional with an advanced bi-directional scan tool or GM's SPS2 software. A locksmith or the dealer will have to connect to your truck's OBD2 port, clear the old keys from the system memory, and pair the new transponders. Expect this service to add an hour of labor to your bill, usually costing around $200–$350 including the new keys.

Find a mobile locksmith or shop on Repairius.