2019 GMC Sierra 2500HD Key Fob Programming Guide

Quick Reference

Step-by-Step On-Board Programming

The 2019 GMC Sierra 2500HD does not support DIY on-board programming for key fobs. The vehicle's security system requires a specialized scan tool to program new key fobs and link them to the vehicle's immobilizer system. This procedure is typically performed by an authorized GMC dealership or an automotive locksmith.

Why a scan tool is required:

Modern vehicles like the 2019 GMC Sierra 2500HD utilize sophisticated anti-theft systems. These systems involve a transponder chip embedded within the key fob and an immobilizer module in the vehicle. For a new key fob to function, the vehicle's computer must "learn" the unique code of the new fob's transponder. This handshake process can only be initiated and completed using a diagnostic scan tool that can communicate with the vehicle's Body Control Module (BCM) and Immobilizer Control Module.

Battery Replacement

The key fob for your 2019 GMC Sierra 2500HD uses a CR2032 coin cell battery.

To replace the battery:

1. Locate the small release button or tab on the side or bottom of your key fob. Press it to release the emergency key blade. Pull out the emergency key.
2. With the key blade removed, you should see a small slot or indentation along the seam of the key fob casing.
3. Carefully insert a small flathead screwdriver or a coin into the slot and gently twist to pry open the two halves of the fob.
4. Once opened, observe the orientation of the old CR2032 battery. Note the positive (+) side and how it's seated.
5. Gently pry out the old battery and insert the new CR2032 battery with the positive (+) side facing the same direction as the original.
6. Carefully snap the two halves of the key fob back together until you hear a click. Reinsert the emergency key blade.

Where to Buy a Replacement Fob

• GMC Dealership:

  • Pros: Guaranteed genuine OEM part, expert programming, often includes key cutting.
  • Cons: Most expensive option. Expect to pay anywhere from $250 to $400+ for the fob and programming.

• Automotive Locksmith:

  • Pros: Often more affordable than a dealership, can program and cut keys on-site (many are mobile), expert knowledge.
  • Cons: Quality of aftermarket fobs can vary; ensure the locksmith uses reputable parts.
  • Cost Expectation: Typically $150 to $300, including the fob, cutting, and programming.

• Online Retailers (e.g., Amazon, specialty key sites):

  • Pros: Cheapest option for the fob itself. Wide variety of OEM and aftermarket choices.
  • Cons: You still need to pay for programming and key cutting separately. Risk of purchasing a non-compatible or low-quality aftermarket fob. Be very careful to match the FCC ID and part number exactly.
  • Cost Expectation: Fobs can range from $30 to $100, but remember to factor in locksmith/dealer programming and cutting costs.

If On-Board Programming Isn't Supported

As established, the 2019 GMC Sierra 2500HD requires professional programming. When purchasing a new key fob, keep the following in mind:

• Cost Expectations: The total cost will include the key fob itself, the service to cut the mechanical key blade (if applicable), and the programming labor. Due to the scan tool requirement and security protocols, these services are not free.
• Immobilizer Transponder: The key fob contains a transponder chip that communicates with the vehicle's immobilizer system. This system is a critical anti-theft feature. If the transponder isn't correctly programmed to the vehicle, the engine will not start, even if the mechanical key fits and turns the ignition (or the "start" button is pressed). This is why DIY programming is not possible for your vehicle.
• Key Blade Cutting: If your new fob includes a physical key blade (either integrated or separate), it will need to be cut to match your existing key. This is typically done by the dealership or an automotive locksmith.

Find a mobile locksmith or shop on Repairius.