P bus and I bus in the Saab 9-3

On the Saab 9-3, not as many control modules as on the Saab 9-5 are connected to a bus system.

The Trionic T7 and the two powertrain systems, EDC 15 and the diesel pump are not connected to the I bus, however. These systems need much faster  communication so that no delays will be noticeable, such as when EDC 15 requests a certain amount of fuel for injection.

Therefore, they are connected to a separate bus called the P bus (Powertrain Bus). Communication on the P bus is ten times faster than on the I bus.

In addition, the P bus is connected to the MIU. The MIU ensures that information which is available on one bus is also available on the other.