Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900) – Full Guide
Operating at 315 MHz with a Philips ID47-family transponder, the Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900) provides passive keyless entry and push-button start functionality for select Acura vehicles. This unit features a four-button layout — lock, unlock, trunk release, and panic — housed in a factory-original casing that matches the dashboard and door-handle antenna frequencies required for proximity detection. Inside the fob sits a Philips-manufactured ID47 transponder responsible for immobilizer handshake with the vehicle’s Body Control Module. Compatible vehicles across the Acura lineup share Honda’s common smart-key architecture, meaning a correctly enrolled Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900) will authenticate seamlessly at ignition and respond to passive-unlock polling within the designated range. Because this is a genuine Honda OEM product bearing the registered FCC ID KR580399900, the device meets all original-equipment RF emission and security specifications.
Transponder and RF Specifications for the Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900)
The ID47 transponder embedded in this smart key belongs to the Hitag 3 platform manufactured by Philips (now NXP Semiconductors under the Philips semiconductor lineage). The ID47 uses an AES-128-based mutual authentication protocol, which replaced the older Hitag 2 system found in earlier Honda and Acura vehicles. This cryptographic upgrade makes the chip substantially more resistant to relay and replay attacks compared to its predecessor.
RF communication between the fob and the vehicle occurs on 315 MHz, the standard frequency for Honda and Acura smart-key systems sold in the North American market. The four-button transmitter sends encrypted rolling-code signals at this frequency, while a separate low-frequency antenna in the fob receives 125 kHz polling signals from the vehicle’s door handles and cabin antennas. This dual-frequency architecture — 125 kHz for proximity wake-up, 315 MHz for command transmission — is what enables the passive entry and start behavior that drivers experience when they approach the vehicle with the fob in a pocket or bag.
Validated Vehicle Fitments
The following Acura models have been validated as compatible with this smart key fob:
- Acura ILX — compact sedan utilizing Honda’s smart-key platform
- Acura MDX (2014–2021) — third-generation and early fourth-generation midsize SUV
- Acura RDX — compact luxury crossover
- Acura RLX (2014–2020) — full-size flagship sedan
- Acura TLX (2015–2020) — first-generation midsize sport sedan
All of these vehicles share Honda’s common immobilizer platform and 315 MHz keyless-entry architecture. The fob’s physical form factor and internal antenna geometry are designed to meet the polling sensitivity thresholds of the antenna modules installed in these specific Acura body styles. Using a genuine OEM unit like the Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900) ensures the internal antenna tuning and battery contact geometry are identical to the factory-supplied original.
Programming and Enrollment Procedures
Enrolling this smart key to a compatible Acura requires dealer-level or professional locksmith diagnostic equipment capable of communicating with Honda’s immobilizer ECU via the OBD-II port. The procedure typically involves the following steps:
- Vehicle identification: Connect diagnostic hardware and confirm the vehicle’s immobilizer generation and existing key count through the Body Control Module.
- Security access: Authenticate to the immobilizer ECU using the appropriate security seed-key exchange. Honda’s newer AES-based systems require tools with current security credentials.
- Key registration: Place the new fob inside the vehicle (usually on the push-button start pad or in a designated spot on the center console) and initiate the key-learn sequence through the diagnostic interface.
- Transponder pairing: The ECU writes an encrypted pairing token to the ID47 chip, binding the fob’s unique cryptographic identity to that specific vehicle.
- RF remote enrollment: The 315 MHz remote functions (lock, unlock, trunk, panic) are registered to the vehicle’s receiver module, which may be integrated into the Body Control Module or a standalone RF receiver depending on the model year.
- Verification: Test passive entry on all doors, push-button start, and all four remote buttons to confirm full functionality.
Professional locksmiths working with this fob should note that Honda’s ID47 system does not support on-board (manual) programming sequences for smart keys. Unlike some older Honda transponder keys that could be added through an ignition cycling procedure, smart-key enrollment is exclusively tool-dependent. Technicians should also verify that the existing keys remain functional after adding a new unit, as some diagnostic workflows erase previously enrolled keys unless the “add key” mode is explicitly selected rather than “all keys lost” mode.
OEM vs. Aftermarket Considerations
Vehicle owners weighing the cost of an original-equipment fob against aftermarket alternatives should understand several trade-offs. The genuine Honda unit carries the certified FCC ID KR580399900, meaning its RF power output, antenna characteristics, and spurious emission levels have been tested and approved by the Federal Communications Commission. Aftermarket clones may function initially but can exhibit reduced passive-entry range, inconsistent wake-up reliability in cold temperatures, or accelerated battery drain due to suboptimal RF tuning.
The Philips ID47 transponder inside an OEM fob is a factory-programmed blank with verified cryptographic integrity. Some aftermarket alternatives use third-party transponder emulators that mimic the ID47 protocol but may not support every programming tool equally. For locksmiths, stocking the OEM version eliminates compatibility variables and reduces callback risk.
Battery replacement on this four-button fob is straightforward — the case separates at a seam near the emergency key slot, revealing a standard CR-series coin cell. No re-programming is required after a battery swap, as the ID47 transponder and rolling-code memory are stored in non-volatile memory independent of the battery.
When to Contact a Locksmith
Owners of compatible Acura vehicles who need a replacement or additional smart key should seek an automotive locksmith experienced with Honda’s ID47 immobilizer platform. Dealership key services are also an option, though independent locksmiths frequently offer faster turnaround and competitive pricing for the same enrollment procedure. The critical requirement is access to diagnostic equipment that supports Honda’s current security authentication — not all general-purpose scan tools carry the necessary credentials for smart-key registration on these vehicles.
Carrying a spare fob is strongly recommended. If the only enrolled smart key is lost or damaged, recovery becomes significantly more complex and costly, often requiring proof of ownership documentation and a lengthier security-access procedure at the ECU level.
Specifications and fitment
| Key type | Smart Key |
|---|---|
| Transponder chip | ID47 |
| Chip manufacturer | Philips |
| Button count | 4 |
| Frequency (MHz) | 315 |
| FCC ID(s) | KR580399900 |
| Region(s) | USA |
| Product type | Smart Key |
| Compatible makes | Acura |
Listed vehicle fitment
| Make | Model | Years |
|---|---|---|
| Acura | ILX | |
| Acura | MDX | 2014–2021 |
| Acura | RDX | |
| Acura | RDX | |
| Acura | RLX | 2014–2020 |
| Acura | TLX | 2015–2020 |
Fitment must be confirmed against the existing key’s FCC ID family and the vehicle’s exact configuration before cutting or programming. VIN or photo verification may be required.
Questions and answers
Which vehicles does Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900) fit?
Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900) is listed to fit Acura applications such as Acura ILX, Acura MDX, Acura RDX, Acura RDX. Confirm the exact year range and the existing key’s FCC ID family before ordering, since fitment can vary by trim and region.
Does Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900) need programming?
Yes. Because it carries a transponder/remote function (chip ID47), it must be programmed (paired) to the vehicle’s immobilizer and, for remote functions, to the keyless-entry system. Many vehicles also require at least one working key to add a new one.
Does the blade need to be cut?
A push-to-start smart key has no traditional blade to cut in normal use, though many include an emergency insert key that can be cut separately.
Is Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900) OEM or aftermarket?
This listing is an aftermarket-grade replacement intended to match the original key’s electronic and mechanical specification. It is not required to carry a vehicle-brand logo and should be matched by FCC ID family and chip type rather than by appearance.
Check Fitment and Key Help
Low Rate Locksmith, a mobile automotive locksmith, can confirm whether Honda OEM 4-Button Smart Key Fob (FCC ID KR580399900) matches an existing FCC ID family and coordinate cutting and programming when the vehicle configuration requires professional service. For dispatch and support, call (833) 439-8636 or email info@lowratelocksmith.com.
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