2021 GMC Sierra 1500 Key Fob Programming Guide

As an ASE-certified electrical technician and automotive locksmith, I frequently get questions from truck owners about programming replacement remotes for modern pickups. The 2021 GMC Sierra 1500 utilizes advanced proximity smart keys. While these systems provide incredible convenience and security, replacing and programming a fob requires specific procedures and, in many cases, specialized equipment.

Here is your comprehensive guide to programming and replacing the key fob for a 2021 GMC Sierra 1500.

Quick reference

Item	Detail
FCC ID	YG0G20TB1 or HYQ1AA (varies by tailgate/remote start options)
OEM Fob PN	13532385, 13537962 (varies by trim and button layout)
Aftermarket Options	Dorman, Autel, Xhorse, various generic aftermarket
Battery Type	CR2032
Programmable On-Board?	Yes, but only if you already have two working fobs.
Cuts Required?	Yes, the internal emergency blade must be laser cut.

Step-by-step on-board programming

General Motors allows you to program a new proximity fob on-board only if you currently have two recognized, working fobs. If you have zero or only one working fob, this procedure will not work due to vehicle security protocols, and you will need a locksmith or dealer.

If you have two working fobs and an uncut/uncoded new fob, follow these steps:

1. Prepare the fobs: Gather your two recognized, working key fobs and your new unprogrammed fob.
2. Access the door lock: Remove the plastic cap covering the physical key cylinder on the driver's side exterior door handle.
3. Trigger programming mode: Insert the emergency key blade from one of your working fobs into the door lock cylinder. Turn the key to the Unlock position five times within 10 seconds.
4. Check the dash: The Driver Information Center (DIC) on your gauge cluster will display a message stating "Ready for Remote #3" (or the next available number).
5. Place the new fob in the pocket: Open the center console and locate the transmitter pocket (usually at the bottom of the console bin or under the front rubber mat). Place your new, unprogrammed fob into this pocket.
6. Program the new fob: Press the engine Start/Stop button once. When the new fob is learned, the DIC will display a message indicating the fob was successfully programmed and is ready for the next remote.
7. Complete the process: Remove the newly programmed fob from the transmitter pocket. Press the Unlock button on the new fob to finalize the pairing sequence.
8. Exit programming mode: Press and hold the engine Start/Stop button for 12 seconds to exit programming mode. Test all fobs to ensure they lock, unlock, and start the vehicle.

Note: If the DIC does not display "Ready for Remote" in step 4, your specific trim level or fleet programming may have on-board programming disabled, requiring a scan tool.

Battery replacement

The 2021 GMC Sierra 1500 fob uses a standard CR2032 battery. When your gauge cluster displays "Replace Battery In Remote Key," it's time to swap it out.

1. Press the small silver release button on the side of the fob and pull out the emergency key blade.
2. Look inside the slot where the key blade was resting. You will see a small pry point.
3. Insert a flathead screwdriver into the pry point and gently twist to split the two halves of the plastic fob shell apart.
4. Carefully remove the circuit board and the old battery.
5. Insert the new CR2032 battery with the positive (+) side facing down toward the back cover.
6. Snap the two halves of the shell firmly back together and reinsert the emergency key blade.

Where to buy a replacement fob

The Dealership:

• Pros: Guaranteed OEM quality, correct FCC ID and part numbers by VIN.
• Cons: Extremely expensive. Expect to pay between $250 and $400 for the fob, plus another $100 to $150 for programming and cutting the emergency blade.

Automotive Locksmith:

• Pros: More affordable than the dealer. A locksmith will ensure you get the right aftermarket or refurbished OEM fob and can cut the laser key blade on-site.
• Cons: You still pay for labor, but the total cost is usually closer to $150–$250 all-in.

Amazon or Online Retailers:

• Pros: Cheapest upfront cost. You can often find aftermarket fobs for $40 to $80.
• Cons: You must match the FCC ID and button layout perfectly. If you buy the wrong frequency or an incompatible aftermarket chip, it will not program. You will still need to pay a locksmith to cut the physical blade and program the fob if you don't have two original keys.

If on-board programming isn't supported

If you have lost all your keys or only have one working key, the truck's immobilizer system blocks the DIY procedure to prevent theft. The 2021 Sierra utilizes a highly encrypted transponder system (often tied into GM's Global B architecture on newer trucks).

In this scenario, a technician must connect an advanced diagnostic scan tool to the truck's OBD-II port. The technician will request a security PIN or perform a timed 10-to-12-minute security bypass to wipe the old keys from the immobilizer memory and marry the new transponder chips to the truck's Body Control Module (BCM). Expect to pay a locksmith or dealer for at least one hour of labor for this service.

Find a mobile locksmith or shop on Repairius.