Honda OEM Smart Key Fob (FCC ID KR5TP-2) – Specs & Fitment Guide

Fitments for the Honda OEM Remote Head Key (FCC ID N5F0602A) – Specs & Info OEM Smart Key Fob (FCC ID KR5TP-2) span several Acura platforms, including the 2022 Acura Integra, the 2022 Acura MDX, and the Acura RDX. Across these vehicles, the fob operates on a 433.92 MHz RF carrier for passive entry and push-button start, while relying on a 4A transponder chip for immobilizer authentication. Each Honda OEM Smart Key Fob (FCC ID KR5TP-2) communicates with the vehicle’s body control module through a cryptographic handshake that must be completed before the engine will crank. Owners replacing the device should expect a dealer-level or advanced locksmith programming session, as the 4A chip protocol requires hardware capable of writing to the immobilizer ECU. When ordering a Honda OEM Smart Key Fob (FCC ID KR5TP-2), confirm the FCC ID printed on the back of the unit matches KR5TP-2, since Honda uses several visually similar fob shells across its lineup that are not cross-compatible.

Honda OEM Smart Key Fob (FCC ID KR5TP-2) — Technical Specifications

The KR5TP-2 is a proximity-based smart key that eliminates the need for a traditional inserted blade during normal operation. Its 433.92 MHz radio frequency is the standard Honda car keys & fobs and Acura frequency for markets outside North America’s 315 MHz band, so verifying the correct regional variant before purchase is critical. The 4A transponder embedded in the fob handles the immobilizer side of the equation, exchanging a rolling cryptographic challenge with the vehicle’s transponder receiver coil located around the push-button start assembly. If the 4A chip response does not match what the immobilizer ECU expects, the starter circuit remains locked out regardless of whether the RF portion of the key successfully unlocked the doors.

Because the FCC ID KR5TP-2 designation is registered with the Federal Communications Commission, the fob’s RF output power and spectral characteristics are fixed at the factory. Aftermarket clones that carry a different FCC ID — or none at all — may operate on a slightly offset frequency or at a different power level, which can reduce range or cause intermittent communication failures with the vehicle’s passive entry antennas.

Vehicle Fitment Details

The validated fitments for this smart key cover a focused group of Acura models. The 2022 Acura Integra uses the fob as its sole proximity key option, pairing it with Acura’s latest-generation immobilizer architecture. The 2022 Acura MDX, a three-row luxury SUV, shares the same KR5TP-2 platform and 4A transponder protocol, which simplifies parts sourcing for shops servicing both vehicles. The Acura RDX also accepts this unit, though locksmiths should verify the specific model year at the time of service to ensure protocol compatibility, since Acura has transitioned between immobilizer generations across RDX production runs.

All three Acura platforms listed above use a passive entry system in which the vehicle’s door-handle antennas continuously poll for the fob’s 433.92 MHz response. When the driver approaches with the device in a pocket or bag, the low-frequency wake-up signal from the car triggers the fob to respond on 433.92 MHz with its encrypted identifier. The car then verifies the response before unlocking the doors. A separate near-field exchange handles engine authorization once the driver presses the start button.

Programming and Registration Procedures

Registering a new or replacement KR5TP-2 fob to one of its supported Acura vehicles involves writing the fob’s unique identifier into the body control module and simultaneously linking the 4A transponder to the immobilizer ECU. This is a two-layer process: RF pairing for remote lock and unlock functions, and transponder registration for engine start authorization. Skipping either layer results in a partially functional key that may lock and unlock doors but will not start the engine — a common complaint when programming is attempted with tools that lack full immobilizer support for the 4A chip.

Automotive locksmiths performing this work should use a diagnostic platform that explicitly supports Acura 4A transponder registration. The 4A protocol differs from earlier Honda/Acura chip families such as the ID47 (Hitag 3), and tools must be updated to handle the newer handshake sequence. Attempting to register the fob under a legacy chip profile will fail silently or throw a generic communication error, which can be misleading during diagnosis.

For vehicle owners, the most practical path is to contact a mobile locksmith experienced with late-model Acura proximity keys or visit an Acura dealership. Either route involves connecting a scan tool to the OBD-II port, entering a security access code sequence, and then placing the new fob in the vehicle’s designated registration position — typically near the push-button start switch — while the tool writes the pairing data. The entire procedure generally takes under 30 minutes per fob when the correct equipment is on hand.

OEM vs. Aftermarket Considerations

Because this is an OEM Honda-branded product, the internal circuit board, antenna tuning, and transponder chip are factory-matched to the specifications that the vehicle’s immobilizer expects. Aftermarket alternatives exist at lower price points, but buyers should be aware that the 4A transponder in some third-party shells may not carry the same silicon revision as the genuine part, which can lead to registration failures on certain tool platforms. The safest approach is to source a unit that carries the KR5TP-2 FCC ID and is sold as a genuine Honda or Acura replacement.

The exterior shell of the fob is also worth noting. OEM units use Honda’s proprietary snap-fit construction and gasket design, which provides a degree of moisture resistance that protects the internal PCB and battery contacts. Third-party shells that mimic the exterior shape may omit or downgrade the gasket, leading to premature corrosion of the battery terminals — a frequent cause of intermittent fob operation that owners sometimes mistake for a dead battery.

Battery and Maintenance

Like most proximity smart keys, the KR5TP-2 is powered by a coin-cell battery housed inside the fob shell. When battery voltage drops below the threshold required for reliable 433.92 MHz transmission, the vehicle’s instrument cluster will display a low-key-battery warning. Replacing the battery involves separating the fob halves — usually with a small flat-blade screwdriver inserted into the seam — swapping the coin cell, and reassembling the shell. No reprogramming is needed after a battery change; the transponder and RF pairing data are stored in non-volatile memory and survive power loss.

Periodic inspection of the emergency key blade slot (if equipped on the specific variant) is also recommended. Some versions of this fob include a concealed mechanical blade for manual door entry in the event of a dead fob battery. Keeping the blade clean and lightly lubricated ensures it can be extracted and used without difficulty in an emergency.