2019 > 2018 > 2017 :)
GPS is always 2mph higher no matter what the speed.
Hi @Vidmo ,Update: This is not contributing. "there’s nothing in the IPC that designates wheel or tire size, that’s all derived from the BCM" .
There is a setting in ForScan "easy mode" for the IPC that affects speedo calibration. Speedometer "Calibration". There is a EU and US setting. For me, EU will always read about 5km/h higher than the GPS speed. US will be within 1 km/h of the GPS speed (I think supposedly to be the accurate reading).Update: This is not contributing. "there’s nothing in the IPC that designates wheel or tire size, that’s all derived from the BCM" .
The tire size is stored in the BCM (Body Control Module). It is measured in millimeters. If you look through all the IPC settings in easy mode or any spreadsheets, you will see there’s no tire size in there. However, if you look at the BCM, regardless of the vehicle, you’ll see settings for the tire size in mm. For example my car is set to 2084mm. Speedometer matches what my phone as well as GPS shows.