Bus Communication

Bus communication, Trionic T7

Bus Communication, Trionic T7:

- Control module, ACC (216)
- Radio connector C (2670)
- Control module, airbag/SRS (331)
- Radio (353)
- CD changer (355)
- Control module PSM (357Dk)
- Control module, Trionic T7 (430b)
- Transmission control module, TCM (502b)
- MIU (540d)
- SID (541)
- Control module (ABS) 547
- Control module STC (565)
- Control module, Trionic T7 OBDII (589b)
- Control module, DICE (628)
- Control module, TWICE (632)

Bus communication, other petrol-engine variants

Bus Communication, Other Petrol-engine Variants:

- Control module, ACC (216)
- Radio connector C (2670)
- Control module, airbag/SRS (331)
- Radio (353)
- CD changer (355) Control module PSM (357Dk)
- Control module, Trionic T5 (430a)
- Control module, TCM (502)
- Control module M2.10.3 (505)
- MIU (540b)
- SID (541)
- Control module (ABS) 547
- Control module STC (565)
- Control module, Trionic T5 OBDII (589a)
- Control module, DICE (628)
- Control module, TWICE (632)


Bus communication, diesel

Bus Communication, Diesel:

- Control module, ACC (216)
- Radio connector C (267c)
- Control module, airbag/SRS (331)
- Radio (353)
- CD changer(355)
- Control module PSM (357Dk)
- MIU (540c)
- SID (541)
- Control module (ABS) 547
- Control module STC (565)
- Control module, EDC 15 (595)
- Control module, auxiliary heater (597)
- Diesel pump (598)
- Control module, DICE (628)
- Control module, TWICE (632)

P-Bus And I-Bus:

A bus is a number of wires on which information is sent digitally and serially. Digital means that the voltage difference between two wires has only two values, about 0 V or 5 V. The information is coded so that different combinations of pulses with values 0 V and 5 V have different meanings.

Serial means that the information is sent in "packets" one after the other in rapid succession.

The bus is divided into the P-bus (Powertrain Bus) and the I-bus (Instrument Bus). Both buses are connected to the main instrument unit (MIU). The buses are electrically isolated from each other.

Only diesel-engine cars and cars with Trionic T7 have a P-bus. Other petrol-engine variants have the same engine management system and automatic transmission as the earlier 900 model (T5, M2.10.3 and TCM) and these have no bus connections.

As in the 9-5, the Airbag and ABS control modules have no bus connections.

The diagnostics instrument is not directly connected to the bus but communicates via DICE, which is connected to the I-bus, and therefore has access to all the control modules connected to the bus.

The P-bus has a data transfer rate ten times higher than that of the I-bus. This is because the P-bus requires information with the least possible delay.

All the information sent from one control module is accessible for all the other control modules on the bus. The MIU is responsible for making information on one bus available to the other bus.

The control modules send out information on the bus at regular intervals. The time between two transmissions depends on the information being transmitted and varies between 10 milliseconds (0.010 seconds) and one second. Information is also transmitted by the control module whenever the information changes.
Transmission of information between control modules occurs on two leads bus+ (green lead) and bus- (white lead). The leads are twisted to increase tolerance to electrical interference.







DICE uses the following information

Part 1:

Part 2:

DICE sends the following information