The XPRESSKIT 556UXL Universal Remote Start Immobilizer Interface Module with Selectable Windings is for larger vehicle keys that won't work with the 556UW Universal Remote Start Interface. It is used when installing remote start products in vehicles equipped with a transponder or RF-based immobilizer system. This type of system uses a small chip imbedded in the ignition key, called a transponder, to transmit a very low powered RF signal. This signal is picked up through an antenna (or coil) around the ignition switch which is then sent to the immobilizer's transceiver. Once the correct signal is received, the immobilizer will enable the ignition and/or fuel systems. If an attempt is made to start the vehicle and the transceiver does not receive a valid code, the ignition and sometimes the fuel systems are disabled. The immobilizer system will then not allow the remote start to successfully start the vehicle. Selectable key windings provide ability to tune kit to specific transponder frequency used by different manufacturers. There's a simple jumper selection to tune kit for European vehicles (60 windings) or domestic (18 windings).
