avopaul

I got a q5 in dianosic gateway code 03041 keep coming on and then the battery gose flat new battery and alternator checked and ok the car will tick over all day then put under load will flatten the battery could it be the clutch pulley slipping under load if I disconnect the little wire going to the alternator I will get 14,4 volts connected only13 voltsand 12.9 at battery any help will be very appreciated thanks paul