One problem related to check engine light on has been reported for the 2015 Audi A8. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2015 Audi A8 based on all problems reported for the 2015 A8.
My car's engine started stuttering and idling very roughly while exiting the expressway. The ec and check engine lights came on. It continued to shutter, and shake, until it shut off. It wouldn't restart, and I had to have it towed to the dealership where I purchased it. The dealer confirmed the issue, and reported the turbos had excessive play and scoring on the surface of the housing, caused by the excessive play in the turbos. Turbochargers needed to be replaced.