Audi A5 High Fuel Use Linked to VANOS Failure

Had the exact same symptoms on my 2014 A4 2.0T. The check engine light combined with high fuel consumption pointed to a faulty inlet camshaft solenoid. The engine misfire and low power issues became more noticeable over time, especially during cold starts. After diagnosis, it turned out the VANOS system had a failing solenoid valve affecting valve timing. This caused incorrect fuel mixture and poor combustion. The repair required replacing the inlet camshaft solenoid and checking the timing chain for any related wear. The job itself is quite serious since it involves working with critical engine timing components. The repair took about 6 hours at the shop. Leaving it unfixed risks further engine damage and continued poor fuel economy. The symptoms you describe match exactly what I experienced, its definitely worth getting checked by a qualified shop that knows these engines. Worth noting that preventive maintenance of the VANOS system can help avoid these issues. Regular oil changes with the correct spec oil are crucial for these engines.

Thanks for sharing your experience. Reading your description matches my situation perfectly, I had the same variable timing issues causing high fuel consumption. My check engine light also came on and stayed on until the repair was done. Curious what the repair ended up costing you? Mine was about 700 Euro for parts and labor at an independent shop specializing in these engines. Since the fix, no engine misfire or timing problems, but wondering if you had any other issues pop up afterwards?

After getting it fixed at my regular shop, the repair cost came to 250 Euro total. They found a defective camshaft solenoid valve that was causing the VANOS system problems. Since the repair, the check engine light has stayed off and fuel consumption returned to normal. No issues with low power or engine performance in the months following the fix. The inlet camshaft timing is now working perfectly and the engine runs smoothly, especially during cold starts. Keeping up with regular maintenance has prevented any repeat VANOS failures. The original symptoms completely cleared up after they replaced the faulty solenoid valve. A proper diagnosis and fix was definitely worth the investment to avoid potential long-term engine damage.

Thanks for the feedback. After taking my A5 to the shop last week, they confirmed it was indeed a VANOS solenoid issue. The repair took around 5 hours and cost me 700 Euro, but the difference is remarkable. The variable timing system is working properly now. Fuel consumption dropped back to normal levels within the first tank, and the check engine light hasnt come back on since. The mechanic showed me the old inlet camshaft components, pretty worn out. They also did a full diagnostic check to ensure no related issues. Just picked up the car yesterday and its running like new. No more rough idle or hesitation. Glad I got it sorted before any serious engine damage occurred. Going to stick to the maintenance schedule from now on to prevent future VANOS failure. This forum really helped point me in the right direction, saved me from getting the runaround at other shops.