Greg4os

2009 Q5 could only read a SD card, not a SDHC card. This means your limit would be 4GB Sd card if you are lucky enough to find one. More common are 2GB SD cards. You are in luck though as this limitation is in the software. There is a software upgrade that can only be applied thru an Audi dealer, known as a campaign that will make your 2009 Q5 (or A4) SDHC compatible to at least 32 GB if not 64 Gb. The campaign addresses issues with traffic (TMC) and reception, the SD reader software is just a part of the upgrade.