your software/hardware/car does not match.

1. I used this product before. When you open the case, it is a FTDI RS232-USB chip + logical level convertor. It's a cheap design for old cars. Theoretically, OBDII is a serial communcation protocal using a RS232 interface using a different logic voltage level. I guess, this product only works with some euro cars (it VW).

2. The software you are using is designed for ELM316 chip, which uses "AT" command set. A ELM chip costs about $30. there is not way for this kind of cheap OBD reader form using this chip. So, some of them use a PIC MCU to simulate ELM316 chip. butstill need a FTDI RS232-USB convertor in order to connect to a PC.

3. please open your reader and tell us which chip it uses

 

4. or your A6 probably uses CAN bus, check your manual first.