The first thing to point out is that GOFAR reads data that car manufacturers provide from the OBD port. Unfortunately odometer (or mileage) is not one of the data sources that car manufacturers had to make available (and so they have not). This means we calculate your odometer as opposed to reading it from the car.
How your car calculates your odometer
Your car calculates your odometer too. The car calculates odometer distance using tyre rotation and has to be accurate +/- 4% in most countries. The odometer reading will be affected by your tyre pressure, tyre size, atmospherics and a number of other small factors.
How odometer is calculated by GOFAR
GOFAR calculates each trip distance based on time and speed and we are usually accurate to within 0.5%.
We then add up all your trips to create a total calculated odometer reading.
The two methods are both educated estimations in other words but can result in different readings and we have created some systems to ensure we match back to the car's odometer.
Here are the main reasons why GOFAR might not match the car's odometer and how you can best ensure it does in future.
Problem 1 - there is a small difference between the car and the GOFAR app
There may be a small 0.5% difference in your car's odometer reading and GOFAR's odometer reading because of the calculation issues outlined above. If you are using GOFAR for logbook, then please be assured that our accuracy is well within accepted tolerances.
Problem 2 - the odometer reading on the app has missed some trips whilst you've been driving "offline"
If GOFAR is under-reporting compared to your car then it is likely that some trips are missing from our calculated total. This happens when your phone and the adapter are not connected during driving. Trips store on the adapter but are not recognised on the app or the server and so our odometer starts under-reporting.
The solution is to connect the app and trips will start to come across and be added to the total
Problem 3 - GOFAR has been unplugged
We cannot track trips when GOFAR is unplugged, so these trips will stay unreported.
Problem 4 - An incorrect value has been entered for starting odometer
You can enter odometer when you set up GOFAR, whenever you do a fill up or by simply updating your vehicle in settings. We will calculate based on whatever value you enter.
Above all, most issues are caused by offline driving and most issues are resolved by driving with your phone and the adapter always connected.