9-3 Arc/Aero (9440) L4-2.0L Turbo (2.0 T) (2004)
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Type
The main instrument unit contains a circuit board and microprocessor with clock, RAM memory and programmable ROM.
The gauge needles are each driven by a separate stepping motor and all graduation, needle, indicator lights and display illumination is achieved with
LEDs. The display and a few indicator lights, e.g. main beam, are dimmed according to the ambient light in daylight, which is controlled by ICM. In the
dark, the driver must adjust all the illumination (graduations, display and some indicator lights) using the brightness buttons on the SID control panel,
SIDC.
There are 6 basic types of instrument available depending on engine and market:
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Tachometer, petrol, 0-7000 rpm
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Tachometer, diesel, 0-6000 rpm
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Speedometer, km/h
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Speedometer, mph and km/h
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Without turbo boost gauge
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With turbo boost gauge
The instruments can be equipped with black or chrome gauge bezels depending on the car model.
The main instrument unit lamps are turned on and the gauges activated via bus messages from other control modules on the I-bus except the Check
Engine lamp, which the engine control module turns on by grounding a pin on the main instrument unit.
For a general description of the car's control modules, see Control Modules, general description.
Power supply, ground and bus communication
