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Sourcing decisions for the Lear Smart Key Fob (FCC ID OHT-4882056) split between OEM and aftermarket paths, and understanding the differences matters for both cost and reliability. An OEM unit carries the original Lear Corporation engineering — validated RF tuning, consistent transponder performance, and factory-grade shell tolerances — while aftermarket variants of this fob may introduce variability in signal strength or mechanical blade fit. The Lear Smart Key Fob (FCC ID OHT-4882056) requires proper proximity programming regardless of sourcing, and skipping verification steps risks a unit that starts the vehicle but fails passive entry or vice versa. For technicians, every variant of this smart key must be confirmed against the vehicle’s security module before delivery to the customer. When replacing the Lear Smart Key Fob (FCC ID OHT-4882056), confirm the FCC ID stamped on the back of the unit matches OHT-4882056 to ensure regulatory and functional compatibility with the target vehicle.

Lear Smart Key Fob (FCC ID OHT-4882056) Technical Specifications

This smart key operates at 433 MHz, a frequency widely used in North American proximity key systems for vehicle platforms that need to balance range, power consumption, and regulatory compliance. The internal transponder is an NXP PCF7939MA, a chip designed for cryptographic mutual authentication between the key and the vehicle’s immobilizer module. The PCF7939MA supports AES-128 encryption, which means cloning through simple read-and-write techniques is not viable — the vehicle’s body control module and the chip engage in a rolling challenge-response handshake each time passive entry or push-button start is attempted.

The emergency blade profile is Y159, which allows mechanical entry to the driver’s door when the fob battery is depleted or the RF circuitry fails. Locksmiths should note that Y159 is a high-security sidewinder-style keyway, requiring either an original key to duplicate from or a code-cut from the vehicle’s key code. Cutting this blade accurately demands a code machine capable of milling internal cuts rather than a standard edge-cut duplicator.

Vehicle Fitment

Based on validated data, this fob is confirmed to fit the 2019 RAM Trucks Pickup. Technicians should verify the specific trim level and configuration of the vehicle before ordering, as RAM offered multiple cab styles and option packages in the 2019 model year. The FCC ID OHT-4882056 designation ties this unit to a specific transmitter design approved by the Federal Communications Commission, and cross-referencing it against the vehicle’s existing key — if one is available — is the most reliable way to confirm compatibility before beginning any programming work.

Programming Considerations for the PCF7939MA Chip

Programming this smart key to a 2019 RAM Pickup requires an advanced diagnostic tool capable of communicating with the vehicle’s RF Hub module and the Secured Gateway Module (SGW). The SGW was introduced across several FCA-platform vehicles in the late 2010s and restricts aftermarket tool access unless proper authorization is obtained. Locksmiths using popular platforms like Autel, SmartPro, or THINKCAR should verify that their tool’s firmware supports SGW bypass or that they have an active AutoAuth subscription, which provides real-time authorization tokens for FCA vehicles.

The procedure generally involves placing the vehicle in programming mode through the diagnostic tool, presenting the new fob within proximity of the steering column or dash-mounted antenna, and allowing the tool to write the key’s transponder identity into the vehicle’s immobilizer memory. Once the transponder is registered, the RF remote functions — lock, unlock, and remote start if equipped — are typically learned in a separate step within the same programming session. Skipping the RF pairing step is a common technician oversight that results in a callback when the customer discovers that proximity unlock does not function despite the engine starting normally.

OEM vs. Aftermarket: Practical Differences

The distinction between an OEM Lear unit and an aftermarket reproduction of this fob extends beyond branding. Lear Corporation manufactures the original equipment version, and its internal antenna geometry, PCB layout, and battery contact design are matched to the vehicle manufacturer’s specifications. Aftermarket reproductions may use a compatible NXP PCF7939MA chip and transmit at the correct 433 MHz frequency, but variations in antenna impedance or shell fit can lead to reduced range on passive entry or inconsistent push-button start performance — particularly in cold weather, when battery voltage drops and marginal signal strength becomes a real problem.

For vehicle owners, the trade-off is straightforward: OEM units cost more but are effectively guaranteed to work at factory-specified range and reliability. Aftermarket units save money upfront but carry a small risk of reduced performance or premature failure. A qualified locksmith can program either version and should be transparent about the source of the replacement unit being installed.

Emergency Blade and Mechanical Entry

The integrated Y159 emergency blade is housed within the fob shell and is released via a small slide mechanism on the back or side of the unit. This blade grants mechanical access to the driver’s door only — it does not start the engine, which requires the transponder chip to authenticate electronically. Vehicle owners occasionally misunderstand this distinction and assume a dead fob battery means they are locked out entirely. In reality, most 2019 RAM Trucks include a push-button start backup procedure: holding the depleted fob against a designated spot on the dash or steering column allows the immobilizer antenna to power the chip inductively and complete the start sequence without any battery in the fob at all.

Locksmiths cutting a replacement Y159 blade should use bitting data from the vehicle’s VIN-derived key code whenever possible. Impressioning or picking the door lock to obtain a working key is feasible but time-consuming given the high-security nature of the keyway. If the customer has lost all keys, the code-cut approach combined with full immobilizer reprogramming is the standard workflow.

Battery and Maintenance

This fob uses a standard coin-cell battery, which should be replaced at the first sign of reduced range or delayed response. A low battery does not immediately disable the key — the vehicle’s immobilizer can inductively power the transponder chip at close range — but it does degrade the passive entry and remote lock/unlock experience. When replacing the battery, avoid touching the circuit board contacts with bare fingers, as skin oils can accelerate corrosion on the battery terminals over time.

Periodic inspection of the Y159 blade for wear or bending is also good practice. A blade that has developed even slight deformation from repeated use may bind in the door lock cylinder, and forcing it risks damaging both the blade and the lock. A locksmith can assess blade condition during any service visit and cut a fresh replacement from code if needed.