| yes, what mschn99 said is spot on. computers think in binary so all they see is zeros and ones, or in many cases like gauges a varying voltage range. The computers are programmed to recognize certain combinations of inputs, and then have a programmed output for that specific input. For instance that fuel filter replacement message... as long as the readings from the sensor are in the safe range the output is zero (no replacement msg displayed), and when it needs replacement it sends a one to the part of the computer that displays that message, and the message shows up. Thats at least a simplified version anyway, I had to take dumb classes with all that junk, so unfortunatley I know more than I care to about it. |