Lear Transponder Key (chip PCF7941) – Fitments, Chip Details & Programming

Programming a Lear Transponder Key (chip PCF7941) requires a diagnostic tool capable of writing to the Philips Semiconductor PCF7941 transponder — a crypto-enabled chip that communicates with the vehicle’s immobilizer module during ignition. The procedure begins with reading the existing immobilizer data and proceeds through a cryptographic handshake unique to each ECU. Locksmiths registering this key must confirm the PCF7941 is in a virgin or erased state before enrollment, otherwise the immobilizer will reject the transponder during the authentication sequence. A Lear Transponder Key (chip PCF7941) enrolled correctly will initialize within two engine-crank cycles and maintain stable communication with the vehicle’s security system. Replacement units of this transponder typically ship with a blank chip that requires on-site programming via pin-code extraction or direct EEPROM access on the immobilizer module.

PCF7941 Chip Architecture in the Lear Transponder Key

The PCF7941, manufactured by Philips Semiconductor, is a combined transponder and remote-control IC. It integrates a Hitag2 crypto transponder engine with a UHF receiver block on a single die, though in this transponder key application the relevant function is the immobilizer authentication layer. The Hitag2 protocol uses a 48-bit proprietary cipher for mutual authentication between the key and the vehicle’s immobilizer control unit. Each PCF7941 chip carries a unique serial number burned at the factory, which becomes the basis for the vehicle-specific cryptographic key pair generated during enrollment.

Because the PCF7941 supports both fixed-code and crypto modes, locksmiths must ensure the correct operating mode is selected before attempting to write vehicle-specific data. Using a tool such as the Abrites FOBIK programmer, Autel IM608, or Zed-Full with the appropriate Chrysler/Dodge/Jeep software license, technicians can read the immobilizer module’s pin code — either from the BCM (Body Control Module) directly or via OBD-II — and then use that pin to authorize new transponder enrollment. Attempting to clone the device without extracting the correct security credentials will fail, as the immobilizer expects a fresh cryptographic pairing rather than a mirrored UID.

Lear Transponder Key (chip PCF7941) Vehicle Fitment Guide

This transponder key, carrying FCC ID IYZ-C01C, covers a range of Chrysler, Dodge, and Jeep vehicles produced between 2005 and 2020. The validated fitment list includes:

• Chrysler 300 — model years 2005 through 2010
• Chrysler Town & Country — model years 2008 through 2016
• Dodge Caravan / Grand Caravan — model years 2008 through 2020
• Dodge Charger — model years 2006 through 2010
• Dodge Journey — model years 2009 through 2020
• Dodge Magnum — model years 2005 through 2008
• Jeep Commander — model years 2006 through 2010

It is worth noting that some of these platforms transitioned to different key types within their production runs. For example, later model-year Dodge Chargers moved to a different immobilizer architecture after 2010, making the PCF7941-based transponder incompatible with those newer vehicles. Locksmiths should always confirm the exact model year and trim level before ordering a replacement unit, since even minor mid-cycle revisions can change the immobilizer hardware.

FCC ID IYZ-C01C — Regulatory and Identification Details

The FCC ID IYZ-C01C is registered to Lear Corporation and covers the integrated remote-start or keyless-entry transmitter portion of the key assembly. While the transponder authentication for engine immobilizer purposes operates at a low-frequency inductive coupling range (typically 125 kHz), the remote functions transmitted under IYZ-C01C operate on a separate radio band. Locksmiths and parts specialists can use this FCC ID to cross-reference the correct aftermarket shell and electronics when sourcing the device. The Lear Corporation branding on this key identifies it as an OEM-tier product, distinguishing it from third-party aftermarket transponders that may use compatible but not identical chip configurations.

Programming Procedure Overview for Chrysler/Dodge/Jeep Applications

The general programming workflow for these Chrysler-platform vehicles equipped with the PCF7941 transponder follows a consistent pattern across the fitment range:

1. Pin code extraction: Connect to the vehicle’s OBD-II port and read the BCM to extract the 4-digit or 8-digit immobilizer pin code. Some older units (2005–2008) store the pin in a less-protected EEPROM area, while later modules may require online calculation through the tool manufacturer’s server.
2. Transponder preparation: Ensure the PCF7941 chip inside the key is in an unprogrammed (virgin) state. If the chip was previously enrolled to another vehicle, it must be erased using the appropriate transponder programmer before it can accept new credentials.
3. Key enrollment: Using the extracted pin code, initiate the “Add Key” function in the diagnostic software. Insert the new key into the ignition barrel (or hold it near the steering column antenna ring on push-button-start variants where applicable). The tool sends the pin code to the BCM, which then opens a brief enrollment window. During this window, the BCM reads the transponder’s UID, generates a new crypto key pair, and writes the vehicle-specific portion back to the PCF7941.
4. Verification: Turn the ignition to the “Run” position with the newly programmed key. The immobilizer indicator lamp should extinguish within two to three seconds, confirming successful authentication. Start the engine to verify full functionality.

Locksmiths performing all-keys-lost procedures on these platforms face an additional step: since no working key exists to prove ownership to the BCM, pin-code-based authorization becomes mandatory. On certain year ranges, the BCM may also need to be reflashed or replaced if it has entered a permanent lockout state after too many failed attempts.

OEM vs. Aftermarket Considerations

The genuine Lear 3-Button Remote Key Fob (FCC ID GQ43VT17T) – Full Guide unit uses an original Philips Semiconductor PCF7941 die, ensuring full compatibility with the vehicle’s immobilizer timing and cryptographic expectations. Aftermarket alternatives are widely available and frequently use the same PCF7941 silicon, but differences in the key shell quality, transponder coil winding, and button-pad durability can affect long-term reliability. For vehicle owners, the practical distinction often comes down to blade fit: an OEM shell seats precisely in the ignition barrel, whereas some aftermarket shells may require minor filing or adjustment. For locksmiths, sourcing a quality aftermarket unit with a confirmed-virgin PCF7941 chip is the most cost-effective approach for routine replacements, provided the programming procedure is followed correctly.

Vehicle owners who have lost all keys to one of the covered models should contact a qualified automotive locksmith rather than attempting dealer-only solutions, as independent technicians with the right equipment can program this transponder on-site — often at substantially lower cost than dealership service departments.