Hi - I had the engine light come on a while ago and had it diagnosed at an Audi specialist - it was down to carbon build up engine cylinder head secondary air ports which is a common issue for older SQ5 - pre 2104. The first time it happened i had it covered by warranty but it reoccurred a year later and it cost me £600 to have the carbon cleaned out. I am now waiting for the light to go on again as i know it is bound to happen. In the US Audi have admitted there is an issue and have extended the warranty to 10 years or 120k miles which ever comes first.
