Audi TT Timing Issues Causing Fuel Economy Drop

I experienced similar symptoms on my 2019 Audi S3 with the 2.0 TFSI engine. The check engine light came on intermittently, accompanied by noticeable power loss and increased fuel consumption. The diagnosis revealed a defective camshaft solenoid valve, which directly affects the variable valve timing system. This is a known issue that can develop even with relatively low mileage. The solenoid failure prevents proper oil pressure control to the camshaft adjusters, leading to timing irregularities. The repair required replacing both the faulty solenoid and its wiring harness, as the electrical connection had also deteriorated. This was not a quick fix, the entire timing cover needed removal to access the components properly. While this is a serious issue that needs immediate attention to prevent potential engine damage, its quite repairable when caught early. The symptoms you describe, poor fuel economy and check engine light, match exactly what happens when the variable timing system starts failing. The key is finding a shop with proper diagnostic equipment that can verify solenoid operation and oil pressure readings. This prevents misdiagnosis and unnecessary parts replacement.

Thanks for sharing your experience. Going through almost the same thing with my TT right now. The check engine light started flashing a few months back and my mechanic also found VANOS solenoid issues causing engine misfires. Definitely sounds like what you had with your S3. Since you went through the repair already, do you remember roughly how much you paid to get it fixed? Also curious if youve had any timing chain or other related problems pop up since the repair?

Glad to help explain the VANOS solenoid repair experience. The inlet VANOS mechanics fault was completely fixed at my trusted workshop, and the engine has been running perfectly since then. The total cost came to 250 Euro for replacing the defective camshaft solenoid valve. No timing chain issues or engine misfires have occurred since the repair was completed six months ago. The check engine light has stayed off and fuel consumption returned to normal levels. The variable timing system is working as intended now. Just make sure your mechanic properly diagnoses the specific VANOS failure point, whether its the solenoid itself or the electrical supply. Getting this diagnosis right is crucial for preventing repeat issues. In my case, the solenoid was the culprit rather than the wiring. The repair cost was reasonable considering the technical nature of accessing and replacing these components. Its much better to address VANOS system problems early before they can cause more extensive engine damage.

After getting multiple recommendations, I found a certified import shop specializing in Audi repairs. Took my TT in last week and their diagnostic confirmed what we suspected, failing VANOS solenoid causing the low power and check engine light issues. The whole repair came to 290 Euro including parts and labor. They showed me the old solenoid which was clearly gunked up and not functioning properly. Since the fix, fuel economy is back to normal and the engine feels much smoother. No more check engine warnings either. Really glad I caught this early before it led to bigger problems. The shop did a great job explaining everything and showing me the failed parts. Much better experience than my previous mechanic who couldn't properly diagnose the VANOS failure. Thanks again for helping point me in the right direction with this issue. The symptoms and repair costs matched up exactly with what you described.