2015 Audi A8 Problems: 5 Known Issues

On the 2010-2015 Audi A8, audi TSB 2030465/12 covers 2010-2015 A8 vehicles with MMI3G+ Navigation, PR code 7T6, for software-group-dependent conditions including random freezes or resets, a blank screen after startup, a stuck splash screen, slow response and listed audio, navigation or Bluetooth complaints. DTC 000384 may be static or 03041 may be sporadic. The bulletin does not cover the later D5 dual-touchscreen system or prove a failed display motor or main unit.

On the 2011-2023 Audi A8, this entry covers two documented electrical problems on the A8. They affect different generations. 2011-2015, flat battery after the car sits: Audi bulletin 2029010 (group 27 13 19, October 2013) applies to all 2005-2015 Audis. It covers owners who find the battery discharged and the car will not start. The bulletin has the battery tested first, then checks for excess current draw while the car is locked. Audi's limit is under 40 mA two hours after locking. Fuses cannot simply be pulled to find the draw, because pulling one can wake the CAN bus and spoil the test. 2019+ with the 48V mild-hybrid system: the cluster may show "Electrical system: fault. Please contact workshop" and/or "Drive system: fault. Please contact workshop". There are three known causes: - Software (bulletin 2070813, July 2023). On cars with active roll stabilization, including 2019-2023 A8s, 2020-2023 S8s and 2020-2021 A8 e quattros, a software problem in the 48V battery management module can set code P0AA100 ("contactor stuck closed"). This can happen when the car has sat for more than 16 minutes, is unlocked and left again, and is then started within 16 minutes. Capacitors in the 48V system are still charged, so the check sees voltage and logs a fault. Audi changed the software in 2024-model production. - Wiring or a sensor on the data bus (bulletin 2073284/2, June 2024). A bad connector (bent or widened pins, shorted wires, a ground cable left unconnected) or a fault in a sensor such as the brake servo pressure sensor can disrupt the data bus. The engine computer then lets the 48V belt starter-generator (BSG) freewheel, so the battery is not charged. Audi warns the car could lose power if you keep driving until the battery is too low. Code U046900 (lost communication with the starter/generator) is a side effect. The bulletin says replacing the starter-generator will not fix it. - A failed BSG. This was the subject of a class action that settled for certain 2019-2023 A8s and related models. Owners in that case alleged warnings such as "Electrical system: malfunction! Safely stop vehicle" along with parking-aid, transmission, traction-control and start/stop warnings.

On the 2011-2018 Audi A8, on adaptive-cruise-equipped 2011-2018 Audi A8 vehicles, ACC may be unavailable and the distance-regulation controller may store C110BF0, adaptive cruise control sensor restricted view. Audi identifies environmental obstruction, sensor contamination, bumper or bracket influence and alignment/calibration conditions as diagnostic branches; the code alone does not prove that the radar sensor has failed.

On the 2011-2023 Audi A8, all A8 models with direct-injection engines (3.0T, 4.0T, 60 TFSI) suffer from severe carbon buildup on intake valves. In direct-injection engines, fuel bypasses the intake valves, leaving them exposed only to oil vapors from the PCV system. These vapors bake onto valve backs as hard carbon deposits over 60,000-100,000 miles. Carbon restricts airflow, causing rough idle, misfires, hesitation, and power loss. Walnut blasting is the common shop method for cleaning the intake valves.

On the 2013-2015 Audi A8 3.0L TFSI, audi TSB 2039995/2 covers 2013-2015 A8 vehicles with the 3.0 TFSI engine when a rattle is heard from the rear timing-chain area for approximately one to three seconds after the first start of the day. Audi attributes the noise to an upper timing-chain tensioner and expressly states that the condition does not lead to damage. The bulletin does not link this noise to cam-correlation fault codes, a jumped chain or bent valves, and it does not cover the 4.2 or 4.0T engines.