Diagnostics concept: General

WARNING: This page is about a different car, the 2003 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.

Demands on car functionality have increased dramatically over the past few years. These developments have focused mainly on the car's electrical system; from the Saab 900 1994 which was introduced with an instrument bus and 4 control modules, the Saab 9-5 and 9-3 with both I-bus and P-bus and 13 control modules to the Saab 9-3 Sport Sedan which contains as many as 30 control modules.

Aside from the I-bus and P-bus system, the Saab 9-3 Sport Sedan will introduce an optical bus, the O-bus, which links together the car's infotainment system. Additionally, an electronically-controlled steering column lock will be included. From the start, 8 of the car's control modules will be programmable with SPS (Service Program System). Most of the control modules have Flash memory and will be subsequently added to the SPS.