2012 Audi A8 Quattro Repair and Maintenance
A guide to problems, costs, maintenance and repair for your 2012 Audi A8 Quattro
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2012 Audi A8 Quattro ProblemsDecreased Power and Fuel Economy from Carbon Buildup
The 2007-2017 Audi A8 with FSI/TFSI, including the W12 are direct injection engines. These engines are subject to carbon buildup in the intake system which can cause power loss, OBD codes and a check engine light, and a rough idle. In normal engines, the engine is cleaned by the gasoline flowing through the injectors and into the intake system, however, the A8 uses direct injection so gasoline does not flow through common carbon buildup areas.
The solution is to remove the intake manifold and professionally clean the intake manifold, intake ports on the cylinder head, and the intake valves. This may need to be done in as few as 20,000 miles.
Popping sounds from the rear of the vehicle may be heard moments after starting the engine, or when slowing to a stop. This noise is from the leak detection pump filling the fuel tank with air, and releasing to retest the system when it finds a fault. The sequence of faults identifying this issue are as follows:
- Succession of loud pops from rear of vehicle
- Pops go away, and fuel economy decreases
- Check engine light illuminates
- OBD trouble code P2404 and/or P0441 is stored
- Engine will not start after refueling (must crank for over 30 seconds)
- Vibration when slowing to a stop
The cause is a valve which is mounted on the front of the intake manifold, commonly called the N80 valve, or EVAP system purge valve. The valve is designed to open under specific circumstances, but a worn valve will remain open at all times, preventing the pressurization of the fuel tank.
Correction of the issue is to replace the N80 valve with the latest revision.
2012 Audi A8 Quattro RecallsCoolant Leaks Into Engine Control Module Causing Stall Or Loss Of Power
A coolant valve may leak onto the engine control module and may cause the engine to stall or lose power. Dealers will replace the coolant valve and inspect for coolant that has leaked through the electrical connector of the engine control module free of charge to resolve the concern.