Strattec Smart Key Fob (FCC ID HYQ4AA) – HU100, PCF7952E, 315 MHz

By Mohammad H. Abdelhadi, ALOA-Certified Master Locksmith, mobile automotive locksmith. Reviewed by Ray Obar, Master Locksmith. Updated June 1, 2026.

Fitments for the Strattec Smart Key Fob (FCC ID HYQ4AA) include the Buick Encore (2013–2026) and the Buick Envision (2016–2020), making it a relevant aftermarket component across nearly a decade of GM-platform Buick models. Over both vehicle lines, the fob communicates at 315 MHz and authenticates through an NXP PCF7952E transponder embedded in the key head. Each Strattec Smart Key Fob (FCC ID HYQ4AA) pairs with the body control module during a rolling-code handshake that governs both passive entry and push-to-start authorization. Owners replacing the device should anticipate a locksmith- or dealer-level programming session, since the immobilizer will not accept an unprogrammed unit. When ordering a Strattec Smart Key Fob (FCC ID HYQ4AA), confirm the HU100 keyway profile and verify production-year compatibility before cutting the emergency blade insert.

Technical Specifications of the Strattec Smart Key Fob (FCC ID HYQ4AA)

The core RF section of the fob operates on a 315 MHz carrier, which is the standard remote-keyless-entry frequency allocated in North America. Modulated signals from the transmitter reach the vehicle’s antenna array positioned around the cabin and trunk area, enabling proximity-based passive entry when the key is within detection range. On the immobilizer side, the NXP PCF7952E transponder chip provides the cryptographic challenge–response sequence that allows the engine to crank. The PCF7952E is a combined RFID transponder and microcontroller in a single package—NXP designed it specifically for automotive immobilizer applications, and it supports both Hitag2 and AES-based authentication protocols depending on the vehicle platform’s configuration.

HU100 Emergency Blade Profile

The physical key housed inside the fob uses the HU100 keyway, a sidebar-style high-security profile found across a wide range of General Motors vehicles. HU100 blanks feature a single-track internal cut pattern with a sidebar that engages milled pockets along the blade edge. Cutting this blade requires either a Lishi-style decoder/pick combination tool or a code-cut machine with the correct HU100 jaw set. Locksmiths should note that the sidebar tolerances on HU100 are tighter than legacy GM keyways, meaning impressioning is not a practical option—code cutting from INSTACODE or equivalent databases is the standard workflow. The emergency blade allows manual door entry and, in some Buick configurations, backup ignition cylinder operation when the fob battery is depleted.

Programming Procedure and Equipment Requirements

Adding the fob to either a Buick Encore or Buick Envision requires a diagnostic tool capable of Security Professional Interface (SPI) access to the body control module. Tools such as the Autel IM608 Pro, Smart Pro by Advanced Diagnostics, or the GM Tech2 with TIS2Web subscription can initiate the key-learning procedure. The programming workflow generally follows these steps:

1. Connect the diagnostic tool to the OBD-II port and establish communication with the BCM.
2. Navigate to the immobilizer/key programming menu and select “Add Smart Key” or equivalent function.
3. Follow on-screen prompts to place the new device within proximity of the steering column antenna ring.
4. The BCM interrogates the PCF7952E transponder chip and, upon successful cryptographic handshake, registers the key’s unique identifier.
5. Cycle the ignition (or press the start button) to verify that the engine starts and the passive-entry functions respond correctly.

All previously programmed smart keys must typically be present during the procedure, because some BCM firmware versions erase existing key slots before re-learning the full set. Automotive locksmiths performing all-keys-lost jobs on these Buick models will need to extract the security PIN or perform an EEPROM read of the BCM to bypass this requirement.

Buick Encore (2013–2026) Fitment Notes

The first-generation Buick Encore, built on GM’s Gamma II platform, used push-to-start ignition across most trim levels from the 2013 model year onward. The fob serves as the sole means of engine authorization on equipped trims—there is no traditional ignition cylinder in push-to-start variants. Over the Encore’s long production run, minor BCM firmware revisions occurred, particularly around the 2017 facelift. Locksmiths should verify the exact BCM part number before programming, as some tool software requires firmware-version-specific routines. The 315 MHz operating frequency remained constant throughout all Encore model years covered by this fitment.

Buick Envision (2016–2020) Fitment Notes

The first-generation Buick Envision, introduced for the 2016 model year on GM’s Delta II platform, also utilizes a proximity-based smart key system. This model line shared significant electrical architecture with other GM crossovers of the same era, which is why the same Strattec unit covers both the Envision and the Encore despite their different vehicle platforms. The HU100 blade profile and 315 MHz RF frequency are identical across both models. One practical difference locksmiths may encounter is antenna placement: the Envision’s larger body means antenna coil locations differ from the compact Encore, which can affect the exact positioning required during the programming handshake step.

OEM vs. Aftermarket Considerations

Strattec Security Corporation is a Tier 1 OEM supplier to General Motors, meaning that Strattec-branded components are not aftermarket in the traditional sense—they are produced by the same manufacturer that supplies the factory assembly line. This distinction matters because some third-party smart key shells on the market use lower-grade plastics and less precise PCB layouts, leading to reduced RF range or intermittent passive-entry failures. The PCF7952E transponder chip itself is sourced from NXP regardless of the shell manufacturer, but the antenna coil winding quality and tuning capacitor tolerances in the RF circuit vary between manufacturers. Purchasing a genuine Strattec unit helps ensure that the 315 MHz transmission characteristics match the vehicle’s receiver sensitivity window.

When to Call a Locksmith

Vehicle owners who need a replacement for a lost, damaged, or malfunctioning smart key fob for their Buick Encore or Envision should contact an automotive locksmith rather than defaulting to dealership service. Qualified locksmiths carry the diagnostic equipment necessary to program the device on-site, often at significantly lower cost than dealer labor rates. The emergency blade also requires precision cutting that mobile locksmith units are equipped to perform using portable code-cutting machines. For all-keys-lost situations—where no working fob exists—a locksmith with BCM PIN extraction capability can complete the job without towing the vehicle to a dealership.

Related help: Buick auto locksmith, car key replacement, car key programming.

Compatible and related keys: Bosma 3-Button Remote Key Fob (FCC ID L2C0007T), compatible GM Mechanical Key Blank (GM39), compatible GM Transponder Key (chip ID13), related key: Strattec 3-Button Remote Key Fob (FCC ID MYT3X6898B), related key: Strattec Smart Key Fob (FCC ID HYQ4EA), compatible Strattec Transponder Key (chip ID13), compatible Strattec Transponder Key (chip ID13), Strattec Transponder Key (chip ID13).