System overview, brief description, cars with EDC 15 engine management system
The two powertrain systems EDC 15 and the diesel pump are not connected to the I-bus. These systems require much faster communication so that there are no noticeable delays when EDC requests a new fuel mass per injection or a new injection timing, for example.
They are therefore 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 EDC 15 has a separate K lead for the diagnostic tool.