Tracks 57 to 70 complete the current flows for the fuel injection system per sé.
On this page, J-Central provides power for the Digifant controller J169, the Lambda sensor’s (G39) heater and the fuel injectors (N30…N33). It takes an input from J169 which is the Digifant signal for the fuel pump (etc.) relay; and it provides a proxy signal from J-Front for the activation of the airconditioning compressor to be used by the Digifant controller.By providing power to the fuel injectors, J-Central has the potential to measure the duty cycle of the injectors and to make that data available on the vehicle network.
As J-Central is located in the air plenum chamber, it has “many” other exciting tasks in store.
J-Central can effectively immobilise the vehicle by not supplying power to J169, the fuel injectors or the ignition system. It would not be sufficient to simply replace the unit to get the vehicle operating as the new unit would not be authenticated against the master or other controllers.
All immobiliser components share keys via a pre-established trust relationship. J-DC, J-Central, J-Front and J-RBody are the core implementors of that policy. Replacement units can only be installed with the help of the unique, removable master (root) key device that would not normally be kept with the vehicle. If that key is “lost”, then all units have to be reflashed and their “secrets” chip replaced and initialised with a new root key if they are to function nominally.