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Join Date: Sep 2002
Location: Vancouver, BC
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Re: Tech: How to reset your service indicator
You and the rest of the board are very welcome - but I have to give credit to the board for the information in the first place!
I believe (I haven't tried it myself so I'm not positive) that when the SIA is reset, it toggles between Inspection I and Inspection II. That is, if you're resetting from Inspection I, it will display Inspection II the next time it trips, and vice-versa.
As for the complex logic in the system itself, it's really very clever. BMW figured out that the easiest way to take driving style into consideration was to count litres of gasoline. When the SIA is reset, the first screen in the sequence above, "SIA 0 l", will switch to "SIA 3250 l". The "3250 l" is a count of litres of gasoline, and when the engine has consumed 3250 litres of gasoline (about 800 gallons) the SIA will hve counted down and will read "0" again, and the Inspection light will come on. If you drive hard or have lots of cold starts, the fuel consumption is much higher, and the light comes on sooner. Lots of low-stress highway miles will give you a longer interval.
By the way, this "SIA 3250 l" counter actually counts down as you drive, so you can see how far through the total you are. I've used this system to measure long-term fuel economy, so I'm pretty comfortable with it's use and it's accuracy. Mine was off by 0.3 litres on 300 litres of fuel, so it's pretty danged accurate!
By the way, if you want to change your oil more often than the SIA indicates, as many do, then use the first stage of the procedure and check the remaining count. If you change twice as often, then change when the reading is "1625", or if you want three times, then change at "2200" and at "1100".