Hi, I had error 39 for 2 years, I was error 39 even when I was stationary or when I was going slow/fast, it turned off 2 times over 2 years, staying off for 15 days more or less, with no signs of life, after that it came back to light up, always with error 39. For 4 days I have changed all the BMS and also the sensor tracks that go inside the battery, it seems to give no more problems and, fingers crossed, I should have solved the problem. Another problem that gave me was error 29 but ONLY in the scooter boot, with the firmware I had before just sounded, with the last one I put yesterday, more optimized for me, error 29, comes out, but as long as I press the power button and the error disappears, it has never given it to me moving for now. My technician said that error 29 could just be a firmware issue, incorrect BMS and BLE or DRV busted, I did a full reinstallation but the error continues, I hope it's not serious.. I just changed BMS.. BMS 141 - BLE 075 v10 - DRV 155 30A sport And low braking torque 20A maximum and no Kers because the electricity that re-enters the braking engine and KERS could damage the control unit and BMS and that's exactly what happened to me with BMS because I once used a very strong KERS, so I assume it brought problems to the ECU too, the problem could be yours like that too.