Bus and Diagnostics Communication

System Overview, Bus And Diagnostics Communication

System Overview, Functions, Cars With Engine Management System Trionic T7

LHD







System Overview, Bus-connected Components, Cars With Engine Management System Trionic T7







1. Trionic, engine management system (430b, 589b)
2. TCM, (Transmission Control Module) (502b)
3. P-bus (Powertrain bus)
4. MIU (Main Instrument Unit) (540)
5. I-bus (Instrument bus)
6. DICE (Dashboard Integrated Central Electronics) (628)
7. SID (Saab Information Display) (541)
8. Audio system, main unit (353)
9. ACC, (Automatic Climate Control) (216)
10. PSM, (Power Seat Memory) (357Dk)
11. TWICE, (Theft Warning Integrated Central Electronics) (632)
12. STC, (Soft Top Control) (565)
13. CDC (CD changer) (355)
14. TC/ABS (Traction Control) (382)

System Overview, Brief Description, Cars With Engine Management System Trionic T7







P-bus and I-bus in the Saab 9-3
In Saab 9-3, all control modules are connected to the bus except for ABS and SRS. On cars with Traction Control, the TC/ABS control module is connected to the bus.

The bus facilitates the transfer of a great deal of information between the control modules on only two leads. The bus is divided into a Powertrain bus (P-bus) and an Instrument bus (I-bus).

The powertrain systems Trionic, TCM and TC/ABS require fast communication so that there are no noticeable delays during torque limitation when shifting and the like.

Trionic, TCM and TC/ABS are connected to the P-bus, which whose speed of data transfer is ten times greater than that of the I-bus.

The P-bus and the I-bus are connected to MIU. MIU is responsible for ensuring that information available on one bus is also available on the other.

The diagnostic instrument is not directly connected to the bus. It communicates via DICE, one of the control modules connected to the I-bus. This provides it access to all bus-connected control modules.

Vehicle speed is important information for many control modules. Because ABS is not connected to the bus, vehicle speed has its own lead from ABS to MIU. MIU then sends information on vehicle speed further on the buses. On cars with Traction Control, MIU receives speed information from TC/ABS via the P-bus.