If you actually get an L4, you will get an AWD vehicle. The issue is that Hertz have a whole load of 2WD versions of mostly the same cars, which they class as K6. Similarly for smaller SUVs, the AWD ones are a Q4, whereas the 2WD ones are a B4. They seem to think that they can allocate a vehicle from either category against the one you booked - which is always going to be the AWD one, as the 2WD Groups do not show up as bookable. I gather from conversations I've had with various of their staff, that is one of the topics of greatest complaint at car allocation time.