System overview, brief description, cars with PSG 16 engine management system
The PSG 16 engine control module is not connected to the I-bus. This system requires much faster communication so that there are no noticeable delays when the engine control module requests a new fuel mass per injection or a new injection timing, for example.
The engine control module is connected by a separate bus called the P-bus (Powertrain Bus). Communication on the P-bus is ten times faster than on the I-bus.
The P-bus is also connected to the MIU. The MIU is responsible for ensuring that information available on one bus is also available on the other bus. Note also that the PSG 16 has a separate K lead for the diagnostic tool.