9-3 Hatchback (9400) L4-2.0L Turbo (B205) (2000)
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Intermittent bus faults
The Trionic T7 and TCM continuously check that all control modules supplying them with information communicate correctly. Intermittent faults in bus
communication with any of these systems will cause diagnostic trouble codes to be generated in the Trionic T7 and TCM. The fault could be caused by
the control module in question having lost its power supply or one of the bus leads.
VR-Bus
VR-Bus
The VR-bus (Valve and Relay bus)is a single-lead bus communications link through which the STC control module controls one relay for each window
lift, one relay for the fifth bow latch motor and the four electromagnetic hydraulic valves.
A bus is understood to be the leads with which information is sent digitally and serially. Digital means that the voltage difference between the leads has
only two values, in this case roughly 0 V and 5 V. The information is coded so that different combinations of 0 V and 5 V pulses have different
meanings.
Serial means that information is sent in "packets" that are sent in succession at a rate of 15 000 bytes/second.
