My OBC consistenly indicates averages 3-4 MPG higher than actual. This causes a 40-50 mile range error right after fillup on a road trip.

I know that there are previous threads regarding this issue but I didn't see any solutions so decided to freshen up the discussion.

The dealer didn't make me feel optimistic regarding a fix.

Has anyone run across a solution? Is everyone's OBC data high or are some correct or even low?

Thanks for your help and my apologies for the redundant thread........

 

Is your Mini stock? Or have you made any mods to it?

 

Not Suprising.

Both my 328i and my MCS report an MPG average of 8-12% higher than the manually calculated number. I mentally adjust the range down by 10% to compensate. I also keep a log of of indicated and calculated MPG for both cars.

As to the fix...

There is a correction factor that can be entered in the MINI "Test Menu". Follow this link for information (and disclaimers) regarding use of the Test Menu".

Test Menu

You will find the correction factor explained in the Test 20 section.

Some words of caution:

1) Mucking about with the Test Menu options *may* be somewhat risky since we do not have the factory instructions for proper operation. That which you read is anecdotal and is not sanctioned by MINI for use by "customers".

2) Before contemplating the entry of a correction factor, collect a lagre enough data set from which you can derive reasonably accurate averages of indicated and calculated MPG. If you car is new, say under 5000 miles, don't bother with the correction factor; as the engine runs-in, the MPG will improve. I will be collecting data from about 15 to 20 fill-ups (after I reach 5000 miles) before I attempt to input a correction factor.

My two pence,

Theo

 

The OBC is not measuring the amount of fuel left in the tank, nor is it measuring the fuel supplied to the engine. The OBC numbers for mpg and range are not intended to be relied upon 100%. Lots of people here mention waiting until their OBC says they have less than 20 miles left before empty, and I think that's crazy! It does seem like the mpg reading should be adjusted by BMW if it's reading consistently high by a certain factor, but other than that, I don't think a "fix" is possible. The current technology is inherently inaccurate.
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WOW, rarely,if ever, have I seen such a truly informative reply...THANKS!!!

 

no mechanical or performance mods...

 

>>WOW, rarely,if ever, have I seen such a truly informative reply...THANKS!!!

I'm just paraphrasing from a much MORE informative recent thread about the OBC (although I suspect you're referring to Koopah, not me!). I'll search and see if I can find it.

HERE IT IS. Check out the posts by edlfrey and MG-BGT.

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