Heres a bit more info for you
Whenever the ignition is turned from position I to position II, the instrument pack and the BCU compare their stored values. If the instrument pack detects that the values are different, it will ‘flash’ the odometer. The odometer will continue to flash until the values have been synchronised. Both units continue to record any distance travelled by the vehicle, even when the display is flashing. If the need arises to change either the BCU or the instrument pack, the new unit will require synchronisation with the existing unit. The value can be synchronised only in an upward direction (the higher of the two values is stored in both units, with the one exception detailed in the next paragraph). Synchronisation of the values can be achieved using TestBook.
If necessary, the odometer readings stored by the BCU and the instrument pack can be reset to 0 kilometres (0 miles) using TestBook. This operation can be carried out only once and then only in circumstances where the current reading is below 160 kilometres (100 miles). This feature is designed to provide dealers with the opportunity of delivering New Discovery vehicles with 0 kilometres (0 miles) displayed on the odometer. This can be carried out after the pre-delivery inspection, once the delivery mileage has been recorded. It should be noted that the values stored by the BCU and the instrument pack must be reset. If only one value is reset then the odometer will flash a miss-match warning, as previously described (depending upon market specification).
