Search "VAG COM" on ebay and you'll get loads of results.

This one for example, is the one I used. Plugs into vehicle and the other end plugs into USB on the laptop.

https://www.ebay.com.au/itm/New-KKL-...AAAOSwJblW~6Hr

Download free ECU Explorer software, and it'll read real time data as the engine is running.