Help with OBC

[Axelf]

I have fitted the OBC and stalk to my car and all went fine, but it seems very inaccurate ... The mileage says I have 200 mile left at 1/4 tank.. MPG and MPH seems very erratic. I have done the 4 test modes by pressing the 2 buttons together, do I need to get if coded to the car? Thanks

 

[Antm72]

Im sure there is a way to calibrate it have read a post on here somewhere explaining how to you may be able to find it or someone with the knowledge will pop up.

 

[Antm72]

HERE.
https://zroadster.org/threads/bmw-z3-obc-calibration.8677/#post-126573