I have a 2000 Audi A4. It has the quattro drive and it's a 5 speed manual tranny. I noticed that when the wife pulled out of the driveway in the snow that only the front tires were spinning. If it's an AWD drive system then why arent the rear tires spinning as wheels. Is the awd system computer controlled because I do have the ABS light on because I need a left rear wheel sensor

 

Google "open differential" and you will gain a little insight as well as from this: The AWD system itself is not really controlled electronically (but keep reading), if a single wheel looses complete traction and begins to spin, all of the power will go to that wheel (this generally only happens when you are stopped or taking off from a driveway, as in your case). The ABS system has a program called Electronic Differential Lock (EDL) which brakes a spinning wheel to prevent this from happening and transfer torque back to the other wheels. If the ABS light is on, EDL will not function. For the most part you wont notice any performance issues EXCEPT in the situation you are describing.