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Subject: Technical details of the service reminder lights... Author: mwong as M.Wong (moderator) : member since December, 2003 : 4933 posts Posted on: 2005-05-04 16:00:41

I am on a similar schedule as garyd. I don't really pay attention to the service lights, but did/will continue to do the bigger "Inspection II" kinds of things at 60K intervals. Oil every 5500 to 6500 miles, plugs done at 70K, radiator at 50K, etc.

However, here are the "Technical details of the service reminder lights."

Mileage is estimated based on the following formula:

e= a(1+t+r)

e=Estimated mileage
a=Actual mileage traveled
t=1 if engine temperature is below operating temperature, else t=0
r=.5 if engine is above 4500 RPM, else r=0

Example: If you traveled 5 miles with a cold engine running at 5000 RPM, the SII computer would actually "estimate" 12.5 miles traveled:

Solving for e:

a=5 (the actual miles traveled)
t=1 (because the engine was cold)
r=.5 (the engine was exceeding 4500 RPM)
e=5 X (1+1+.5)=12.5 estimated miles (from a trip of only 5 miles)

Once the computer reaches a certain count value (about 7,500 miles for Oilservice and 15,000 miles for inspection, varies from years/models), it will illuminate one of the service lights (oilservice or inspection).


(info from PeakeResearch)

M.Wong
E38 2000 740iL Orient Blue
E39 2003 540i/6 Sterling Gray (European Delivery)
E30 1987 325i Royal Blue (Passed on to a new family.)

• inspection based on time or miles? - bavariancowboy 2005-05-04 13:33:45 (891 views)
  • Re: inspection based on time or miles? - garyd 2005-05-04 14:30:11 (665 views)
    • Technical details of the service reminder lights... (pic) - M.Wong 2005-05-04 16:00:41 (19666 views)
      • Re: Technical details of the service reminder lights... - garyd 2005-05-04 16:38:34 (1056 views)
        • It is a strange way to calculate - M.Wong 2005-05-04 17:12:16 (862 views)