Subaru Remote Head Key (FCC ID TOY43R) – Specs, Fitments & Info

Operating at 315 MHz with a Subaru H transponder, the Subaru Remote Head Key (FCC ID TOY43R) integrates remote-lock functions and engine immobilizer authentication into a single housing. This unit is built around the TOY43R keyway — a blade profile shared across several Subaru platforms from the mid-2010s through the early 2020s. Inside the fob sits the Subaru H chip, which handles the cryptographic handshake between key and vehicle ECU during ignition. Compatible vehicles span from compact hatchbacks to midsize SUVs, all sharing the same immobilizer architecture. A correctly enrolled Subaru Remote Head Key (FCC ID TOY43R) will start the engine only after the on-board computer validates the transponder signal, while the integrated remote buttons handle door lock and unlock commands wirelessly at the 315 MHz operating frequency. The Subaru Remote Head Key (FCC ID TOY43R) remains one of the more commonly encountered remote head keys in the Subaru aftermarket parts ecosystem.

Technical Specifications of the Subaru Remote Head Key (FCC ID TOY43R)

The FCC ID designation — TOY43R — doubles as the keyway identifier. This blade profile features a high-security laser-cut pattern that must be precision-milled on a code machine or duplicated from an existing working key using a Lishi TOY43R pick/decoder tool. Automotive locksmiths will recognize the TOY43R keyway as a standard in Subaru’s lineup during this era, making it a familiar cut for shops that service Japanese makes.

The transponder inside is classified as Subaru H. This chip family employs a rolling-code or challenge-response protocol that prevents simple relay attacks. During key programming, the vehicle’s immobilizer control module writes a unique cryptographic seed to the chip, binding it to that specific VIN. Without successful enrollment, the blade may turn the ignition cylinder, but the engine will crank without starting — the ECU kills fuel delivery when it cannot authenticate the transponder signal.

The RF portion of the remote head key transmits at 315 MHz, the standard frequency band for North American Subaru vehicles. This frequency handles keyless entry functions — locking, unlocking, and in some configurations, panic activation. It is separate from the transponder’s low-frequency immobilizer communication, which occurs through inductive coupling when the key is inserted into the ignition barrel.

Validated Vehicle Fitments

The following Subaru models and model years have been confirmed as compatible with this remote head key:

• Subaru Ascent — 2018
• Subaru Crosstrek — 2018 through 2022
• Subaru Impreza — 2016 through 2023
• Subaru XV — 2017 through 2022

Note that the Subaru XV and Subaru Crosstrek share a platform (the XV designation was used primarily in markets outside North America, while Crosstrek was the North American branding). Despite their overlapping architecture, the fitment years listed above reflect verified compatibility ranges and should be treated independently when ordering replacement keys.

The Subaru Impreza’s fitment window is the broadest here, running from 2016 to 2023 — a span that covers the fifth-generation Impreza’s full production run. Meanwhile, the Ascent’s single-year listing at 2018 corresponds to the model’s launch year; later Ascent model years may use a different key type or FCC ID and should be verified before assuming the same part applies.

Programming Considerations for Locksmiths

Enrolling this key to a Subaru requires a diagnostic tool capable of communicating with the vehicle’s immobilizer ECU. Most professional automotive locksmith platforms — including Autel, Smart Pro, and similar advanced programmers — support Subaru H transponder registration. The process typically involves connecting to the OBD-II port, accessing the immobilizer module, and following a guided procedure that writes the new key’s transponder data into the vehicle’s approved key list.

One critical detail: many Subaru immobilizer systems require at least one registered working key to add another. When all keys are lost, the procedure escalates considerably. Some platforms support all-keys-lost scenarios for Subaru H vehicles via pin code retrieval or direct EEPROM access on the immobilizer module, but this demands additional equipment and expertise. Locksmiths should verify their tool’s coverage for the specific model year before committing to the job.

Blade cutting is equally important. The TOY43R keyway requires a laser-cut (track-cut) machine. Code-original cutting from bitting data is the most reliable approach, but Lishi-based decoding from an existing key can also produce an accurate duplicate. The blade must seat cleanly in the ignition cylinder — a poorly cut TOY43R blank can damage wafers inside the lock, creating a more expensive repair.

OEM vs. Aftermarket Considerations

OEM remote head keys sourced through Subaru dealerships come pre-loaded with the correct transponder type and are typically guaranteed to program on the first attempt. The trade-off is cost — dealer-sourced keys carry a significant price premium over aftermarket alternatives.

Aftermarket versions of this key are widely available from locksmith supply distributors. Quality varies by manufacturer, but reputable aftermarket blanks use the same Subaru H chip specification and 315 MHz RF circuitry. When sourcing aftermarket, verifying the FCC ID (TOY43R) and transponder type before purchase prevents mismatches that waste shop time. A legitimate aftermarket unit should function identically to the OEM part once properly cut and programmed.

When Vehicle Owners Should Contact a Locksmith

For owners of the Subaru Impreza, Crosstrek, XV, or Ascent models listed above, a qualified automotive locksmith can cut and program a replacement remote head key on-site — often at a lower total cost than a dealership visit. Mobile locksmith services are especially convenient because the vehicle does not need to be towed to a shop or dealer. Look for a locksmith who confirms Subaru H programming capability and carries TOY43R blanks before scheduling the appointment. Confirming these specifics in advance ensures the technician arrives prepared and the job completes in a single visit.