10.25.1. Features of a design

Install an immobilizator on the Ford Fusion cars. This electronic device is intended for prevention of unauthorized launch of the engine by a rupture of electric chains of a control system of the engine.
Immobilizator consists of the control unit and a control lamp in a combination of devices, the communication coil in the lock of ignition, working key in the remote control. Operating modes of an immobilizator are displayed by inclusion of a signaling device and signals of the buzzer which is built in it.
The control unit of an immobilizator is connected to the controller through the diagnostic line. The control unit has the built-in relay which connects diagnostics block to the controller or disconnects it. If the diagnostic unit is not connected to a diagnostic block, then the relay disconnects a diagnostic chain and the line is used for communication of the controller and the control unit. At connection of the device to a block of diagnostics of the relay closes a diagnostic chain that allows to carry out exchange of information between the device and the controller. However the control unit of an immobilizator has a priority in front of the diagnostic unit during the work with the controller, in case of need the control unit interrupts contact of the controller with the device (for example, for exchange of information between the control unit and the controller at launch of the engine).
The control unit of an immobilizator and the controller can be in one of two states:
1 state — function of an immobilization is switched off. In this state the control unit of an immobilizator is switched off, communication between it and the controller is absent, blocking of the engine is impossible;
2 state — function of an immobilization is included. In this state blocking of the engine is possible, the unblocking is carried out by receiving by the controller of the correct password from the control unit of an immobilizator.