Bosma Remote Head Key (FCC ID KOBDT04A) – PCF7941, 433 MHz, Y160

Used across a wide range of Chrysler, Dodge, and Jeep platforms from 2004 through 2014, the Bosma Remote Head Key (FCC ID KOBDT04A) combines mechanical ignition access with integrated remote-lock electronics in a single housing. Each Bosma Remote Head Key (FCC ID KOBDT04A) pairs a PCF7941 transponder with 433 MHz RF transmission, allowing the device to communicate with both the vehicle’s immobilizer module and its body control module simultaneously. For automotive locksmiths, this remote head key demands attention to transponder enrollment sequence and RF synchronization — two distinct programming steps that must both succeed for full functionality. A properly provisioned Bosma Remote Head Key (FCC ID KOBDT04A) delivers seamless keyless entry alongside conventional turn-start ignition through the Y160 keyway profile.

PCF7941 Transponder and 433 MHz Operation in the Bosma Remote Head Key (FCC ID KOBDT04A)

The PCF7941 is a dual-function chip that handles both the cryptographic handshake required by the immobilizer system and the rolling-code generation used for remote keyless entry. In this unit, the transponder side authenticates with the vehicle’s Wireless Control Module (WCM) or Sentry Key module during ignition events, while the RF side broadcasts lock, unlock, and trunk-release commands at 433 MHz. This split architecture means the key must be programmed on two separate channels — transponder first, then remote — and failure to complete either step will leave part of the key’s functionality inoperative.

The 433 MHz operating frequency distinguishes this product from some North American OEM variants that use 315 MHz. Technicians should verify frequency compatibility against the target vehicle’s receiver module before beginning remote programming. Mismatched frequency will allow the transponder to start the engine but will prevent all remote-lock functions from responding, a common diagnostic pitfall when sourcing aftermarket remote head keys for these Chrysler-platform vehicles.

Y160 Blade Profile and Mechanical Specifications

The integrated key blade uses the Y160 keyway, a standard profile across many Chrysler, Dodge, and Jeep models produced during this era. The Y160 is a high-security sidebar design that requires either an original key for code cutting by impression or an accurate key code pulled from the vehicle’s VIN through authorized dealer databases or locksmith code-retrieval services. Standard edge-cut duplicating machines will not produce a functional Y160 blade — a dedicated Chrysler-profile jaw or clamp is required on a code-cutting machine.

When cutting the blade for this remote head key, technicians should confirm that the blade seats fully into the ignition cylinder and rotates without binding before attempting any electronic programming. A blade that is marginally out of specification can still turn the cylinder but may not position the transponder antenna loop correctly relative to the WCM’s read coil, resulting in intermittent no-start conditions that mimic a failed transponder enrollment.

Validated Vehicle Fitments

The following vehicles have been validated for compatibility with this key:

• Chrysler 200 — 2011 through 2014
• Chrysler 300 — 2005 through 2010
• Chrysler Aspen — 2007 through 2009
• Chrysler Sebring — 2007 through 2010
• Dodge Avenger — 2008 through 2014
• Dodge Caliber — 2006 through 2012
• Dodge Charger — 2006 through 2010
• Dodge Durango — 2004 through 2009
• Dodge Nitro — 2007 through 2012
• Jeep Cherokee — 2008 through 2012
• Jeep Commander — 2006 through 2010
• Jeep Grand Cherokee — 2005 through 2010

Across these fitments, the fob interacts with Chrysler’s Sentry Key immobilizer architecture. While the underlying transponder protocol is consistent, minor differences in body control module firmware between model years can affect the remote-pairing procedure. Technicians working on early-production 2005 Chrysler 300 units, for example, may encounter a different remote enrollment sequence than what is documented for 2009-and-later models sharing the same platform.

Programming Considerations for Locksmiths

Transponder enrollment for this device typically requires a diagnostic tool capable of interfacing with Chrysler’s Sentry Key Immobilizer Module (SKIM) or the later-generation WCM found in 2008-and-newer platforms. The programming workflow generally proceeds in two phases:

1. Transponder registration: The PCF7941 must be written into the immobilizer’s key memory slot. Most professional locksmith programmers support this via OBD-II, though certain year-model combinations may require a PIN code retrieved from the vehicle’s VIN or direct EEPROM access on the module.
2. Remote synchronization: After transponder enrollment, the 433 MHz remote function is paired to the body control module through a separate on-board procedure. This step is often achievable without diagnostic equipment — many of these Chrysler-platform vehicles support a manual remote-learn mode activated through a specific ignition-cycle sequence — but the exact steps vary by model year.

If the remote portion of the key fails to pair after transponder enrollment, technicians should confirm that the battery in the fob housing is fresh and correctly oriented. The PCF7941’s RF transmission draws more current than the transponder’s passive antenna coil, and a marginal battery that passes a transponder test can still fail to generate adequate RF output at 433 MHz.

OEM vs. Aftermarket: What Vehicle Owners Should Know

Vehicle owners seeking a replacement for a lost or worn remote head key will encounter both OEM Chrysler-branded units and aftermarket alternatives like this Bosma product. The primary advantage of an aftermarket unit with the correct FCC ID — KOBDT04A in this case — is cost: aftermarket remote head keys typically run a fraction of dealer pricing while using the same transponder chip and frequency specification.

The trade-off is in housing fit and finish. OEM keys undergo tighter injection-mold tolerances and use branded rubber button pads that tend to resist wear longer under daily use. Aftermarket housings can vary in tactile feel and long-term button durability, though the electronic internals — the PCF7941 chip and 433 MHz transmitter circuit — are functionally identical once programmed. For owners on a budget, this key represents a practical choice, provided it is cut and programmed by a qualified locksmith or dealer technician.

Regardless of whether an OEM or aftermarket unit is selected, all keys programmed to these Chrysler-platform vehicles occupy a finite number of memory slots in the immobilizer module — typically eight. If all slots are full, an existing key must be erased before the new one can be enrolled. Owners should inform their locksmith of how many keys are already programmed to the vehicle to avoid unnecessary diagnostic steps.