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Bus communication

Bus communication

Bus communication, Viggen



Control module ACC (216)

Radio connector C (267c)

Control module airbag/SRS (331)

Radio (353)

CD changer (355)

Control module PSM (357Dk)

Trionic T7 control module (430b)

MIU (540d)

SID (541)

Control module, ABS (547)

Control module STC (565)

Trionic T7 OBDII control module (589b)

Control module, DICE (628)

Control module, TWICE (632)


Bus communication, other petrol engine variants



Control module ACC (216)

Radio connector C (267c)

Control module airbag/SRS (331)

Radio (353)

CD changer (355)

Control module PSM (357Dk)

Trionic T5 control module (430a)

Control module, TCM (502)

Control module M2.10.3 (505)

MIU (540b)

SID (541)

Control module, ABS (547)

Control module STC (565)

Trionic T5 OBDII control module (589a)

Control module, DICE (628)

Control module, TWICE (632)


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)

EDC 15 control module (595)

Control module, extra heater (597)

Diesel pump (598)

Control module, DICE (628)

Control module, TWICE (632)


P bus and I bus


By bus is meant leads in which information is transmitted digitally and serially. By digital is meant that the voltage difference between the two leads can have only two values, approx. 0 and 5 V. The information is coded so that different combinations of pulses with the values 0 and 5 V mean different things.

Serial means that the information is sent in ”packets” which are transmitted one after the other in rapid succession.

The buses consist of a P bus (Power-train Bus) and an I bus (Instrument Bus). Both buses are connected to the MIU (main Instrument Unit). The buses are electrically isolated from each other.

Only diesel cars and Viggen have a P-bus. The other petrol engine variants have the same engine management system and automatic transmission as in the earlier 900 model (T5, M2.10.3 and TCM), which are not bus-connected.

As in the 9-5, the Airbag and ABS control modules are not bus-connected.

The diagnostic tool is not connected directly to the bus but communicates via the DICE, one of the control modules connected to the I bus, and so has access to all control modules connected to the bus.

The data transmission rate of the P bus is ten times greater than that of the I bus. The reason for this is that the power-train system requires information with the minimum possible delay.

All the information sent from one control module is accessible for all other control modules on the bus. The MIU is responsible for ensuring that information available on one bus is also available on 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 sent and varies between 10 milliseconds (0.010 seconds) and 1 second. Information is also sent out by the control modules 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.

TWICE uses the following information for the theft protection

Information

Values

From

The value depends on the following sensor input, signal or function

SID buttons

Clear, Set, Trip Down, Trip Up, Night Panel

SID

Buttons.

TWICE uses the information to disconnect the glass breakage sensor and angle sensor. For this, the “Night Panel”-button is used with the key removed from the ignition.

Soft top position

Up/In motion/Down

STC

Switches on top of windscreen frame, Soft top cover switch.

TWICE uses the information to disconnect the glass breakage sensor when the hood is open and stowed and to allow the luggage compartment to be opened or not.

Theft protection information



MIU

Value created in MIU when immobilizer code is programmed in TWICE

TWICE uses the information for the immobilization function.

Diagnostics communication



DICE/diagnostic tool

Control module should be powered and the bus leads intact

See Bus and diagnostics communication





TWICE sends the following information for the theft protection

Information

Values

Used by

The value depends on the following sensor input, signal or function

Immobilization

ON/OFF

MIU (Cars with B204)

Immobilizer function.

MIU uses the information to allow the engine to be started.

EDC 15 uses the information to allow the engine to be started.

Text message



SID

Anti-theft alarm function and central locking system function.

SID uses the information to show the text message for the theft protection.



Key correct

ON/OFF

Audio

CDC

Immobilizer function.

The audio system and CD changer use the information for the audio system theft protection.



Hazard flashers

ON/OFF

DICE

Anti-theft alarm function and central locking system function.

DICE uses the information to activate the hazard flashers when the alarm is activated.



Diagnostics



DICE/diagnostic tool

Control module should be powered and the bus leads intact.

See Bus and diagnostics communication