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.

Trionic T7, on the other hand, is not connected to the I-bus. This system requires considerably faster  communication to avoid noticeable delays, e.g. when Trionic T7 requests a certain fuel mass for injection.

Trionic T7 is therefore 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.