Mark 1

I Have tried disengaging All the censors but still no enjoy and now the management light stays on going from bad to worst

Could I take advice off you guys here's my question, I just had my yamaha yzf125 abs inspected from motorbike trader my gears where all working yesterday and today he inspected the bike alone because I was distracted by my puppies now when the bike is put into 1st or 2nd gear the bike stalls it never did before, has he done something to cause this as on his work sheet he pointed this as a fault can I do anything to restore the gears to normal. Would appreciate your advice guys.