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Old 05-16-2008, 09:01 PM   #2 (permalink)
cfg83
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1999 Saturn SW2 - '99 Saturn SW2 Wagon
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peterj -

Sounds pretty accurate to me. I think the SG is relying on the "lowest common denominator" set of information that it can rely on across a variety of car platforms.

Quote:
Originally Posted by peterj View Post
...

The most popular OBD device is the ScanGuage II, but I have been unable to determine which OBD parameters it uses to calculate instantaneous mileage. It seems clear that it must use MAF, but it could bias that based on other values. It is also not clear if it makes use of optional parameters such as FI if they are available. (Any clarification here would be helpful.)

...

Many thanks for any addition and/or clarification on these issues.
Your post just made me realize that an "OBDII Output Simulator" would be a good way to reverse engineer the SG algorithms.

CarloSW2
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