One problem related to engine failure 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.
Regular driving east bound on I-80 and after going up a hill my car couldn't go over 3500 rpms. Thought it was the ecu putting it into limp mode because of weather conditions. Turned out both my turbos blew at 67,000 miles and lead to total engine failure with metal shavings reaching the exhaust and loitering the oil pan.