On my AM, there is a button that changes the T1 to T2. I don’t know what thar does but it seems like it tracks mileage. I don’t know how to reset it to zero.
The button toggles between two trip meters, T1 and T2. If you press it, it should flick over between the two. To reset the reading, keep the button pressed in for a few seconds. Should work on both T1 and T2.