[MadeMan]

pawn Код:

if(PRESSED(KEY_SUBMISSION))
    {
        if(IsPlayerInAnyVehicle(playerid))
        {
            new vehicleid = GetPlayerVehicleID(playerid);
            if(IsPlayerInDM[playerid] == 0)
            {
                RepairVehicle(vehicleid);
                PlayerPlaySound(playerid, 1133, 0.0, 0.0, 0.0);
            }
            else
            {
                SendClientMessage(playerid, COLOR_RED,"Use /exitdm before you can Fix your Vehicle!");
            }
        }
    }

And you don't need SetVehicleHealth, RepairVehicle does that already.