Had a problem recently with my A5 having to be repaired by a local garage.
Which would be the better to use to find the reason for any problem and repair in future.
A OBD2 ELM327 via Android phone or PC based VCDS via a OBD2 interface cable.
VCDS is definitely better - £225 for the 3-VIN version from Gendan.
Marque specific code reader anytime.
Use and ELM and you'll most likely get "manufacturer specific code" or the wrong or missing info altogether.
