2015 GMC Sierra 2500HD Key Fob Programming Guide

Quick reference

Step-by-step on-board programming

The 2015 GMC Sierra 2500HD offers a convenient on-board programming procedure for its keyless entry remote (RKE) functions. This allows you to program new or replacement key fobs yourself without needing specialized tools or a trip to the dealership. This procedure will not program the immobilizer transponder, which is a separate component within the key that allows the vehicle to start.

Important Note: Ensure you have all key fobs (including existing, working ones) with you before starting this procedure. All remotes will be erased from the vehicle's memory during the programming process, and any remotes not programmed at this time will no longer work.

1. Enter the vehicle and close all doors.
2. Insert the key into the ignition.
3. Turn the ignition to the "ON" position (without starting the engine) and then back to "OFF" three times consecutively within five seconds. The vehicle's horn should chirp, or the dash indicators should flash to confirm it has entered programming mode.
4. Press and hold the LOCK and UNLOCK buttons simultaneously on the first key fob you wish to program. Continue holding for approximately 15 seconds. The vehicle's horn should chirp or the dash indicators should flash twice to confirm successful programming of that remote.
5. Release the buttons.
6. Repeat step 4 for any additional key fobs you wish to program. You must do this for all remotes (new and existing) you want to use with the vehicle.
7. To exit programming mode, turn the ignition to the "OFF" position and remove the key. Test all programmed remotes to ensure they function correctly.

Battery replacement

Replacing the battery in your 2015 GMC Sierra 2500HD key fob is a straightforward process:

1. Locate the small indentation or slot on the side of the key fob body. Use a small flathead screwdriver or a coin to gently pry open the two halves of the fob.
2. Carefully separate the two halves. You'll see the circuit board and the battery.
3. Note the orientation of the existing CR2032 battery (positive (+) side up or down).
4. Remove the old battery by gently prying it out.
5. Insert the new CR2032 battery with the correct orientation.
6. Align the two halves of the key fob and press them firmly together until they snap shut.
7. Test the key fob to ensure it's working correctly.

Where to buy a replacement fob

When considering a replacement key fob for your Sierra, you have several options:

• Dealership: This is generally the most expensive option. You can expect to pay anywhere from $200 to $350 or more for a new OEM key fob and programming. The advantage is a guaranteed genuine part and professional service, but the cost can be prohibitive.
• Locksmith: A qualified automotive locksmith can often provide and program a new key fob for significantly less than a dealership, typically in the range of $150 to $250. They often have access to both OEM and high-quality aftermarket options, offering a good balance of cost and expertise. They can also cut new key blades if needed.
• Amazon/Online Retailers: You can find aftermarket key fobs on sites like Amazon for as little as $20 to $50. While this is the cheapest option for the fob itself, remember that these are often remote-only devices, and you'll still need to factor in the cost of cutting a new key blade (if integrated) and programming the immobilizer transponder (if applicable and if not programmable on-board). Also, be wary of very cheap fobs as quality can vary. Always ensure the FCC ID and part numbers match for compatibility.

If on-board programming isn't supported

While the remote keyless entry portion of your 2015 GMC Sierra 2500HD key fob can be programmed on-board, the immobilizer transponder chip that allows your vehicle to start requires specialized equipment. If you need a new key that will actually start your truck (not just unlock the doors), you will need the transponder chip programmed.

This typically requires a scan tool that can communicate with the vehicle's onboard computer. This service is usually performed by:

• An automotive locksmith: They possess the necessary diagnostic tools to program the transponder chip and cut new key blades. Their cost will generally be lower than a dealership.
• A GMC dealership service center: They can also perform this service. Be prepared for higher labor costs.

Cost Expectations for Transponder Programming: Expect to pay an additional $75 to $150 or more for transponder programming, beyond the cost of the key fob itself. This brings the total cost closer to what a locksmith or dealership would charge for a complete key replacement, but shopping for the parts and labor separately can sometimes save you money if you find a good deal on the fob itself.

Key Cutting: If your new key fob includes an integrated key blade and you need a new physical key, it will need to be professionally cut to match your vehicle's locks. Locksmiths and dealerships can do this. The cost for key cutting is usually in the $10-$30 range.

Find a mobile locksmith or shop on Repairius.