Audi S1: Flashing CEL with Power Loss and Smoke

Had similar symptoms on a 2012 Audi A3 1.4 TFSI. The rough idle and power loss pointed to a failing PCV valve system. The smoke from exhaust was engine oil being pulled through due to excessive crankcase pressure. The ventilation system failure caused oil to be drawn into the intake, leading to carbon buildup on valves. This explained the weak performance and check engine light. The emissions were affected since oil was being burned, making it a serious issue requiring prompt attention. The repair involved replacing the complete PCV assembly and cleaning the intake valves. The valve cleaning was necessary because oil residue had already accumulated. This is a known issue on these engines when the crankcase ventilation fails. After repair, the idle smoothed out immediately and power returned to normal. The check engine light cleared and stayed off. Most importantly, the exhaust smoke disappeared completely. This repair should not be postponed as continued operation can lead to increased oil consumption and potential catalytic converter damage. The symptoms match classic PCV system failure, which affects many VAG engines from this era.

Thanks for sharing your experience! This matches exactly what my S1 was doing. Did the mechanic also need to clean the throttle body during the repair? Just curious about the total cost you ended up paying, as I am getting different quotes. Also, has the malfunction stayed fixed or did you notice any other valve-related issues since the repair? My main concern is passing the upcoming emissions test, so I want to make sure this gets resolved properly the first time around during maintenance.

Quick update on my A3 repair: The PCV valve replacement completely resolved the issues and the car has run perfectly since. The mechanic did clean the throttle body as part of the maintenance service while fixing the crankcase ventilation system. Total cost came to 360 Euro for the complete job including parts and labor. The idle is now smooth and steady, power delivery is back to normal, and most importantly no more smoke from the exhaust. I have had zero valve-related problems in the months following the repair. The emissions test should not be a concern once the PCV system is working correctly, as the excess oil burning issue gets eliminated. Make sure your mechanic does a thorough cleaning of the intake system while they have everything apart. The maintenance work may seem expensive but fixing it properly the first time prevents more costly problems down the road.

After reading about similar issues, I finally took my S1 to a local independent Audi specialist. The diagnosis confirmed what was discussed here, a failed PCV system. The repair took about 4 hours total. They replaced the PCV valve assembly, cleaned the throttle body, and performed a thorough intake valve cleaning to remove oil residue. Total cost came to 420 Euro, which included all parts, labor, and cleaning services. The maintenance work was definitely worth it, the engine runs like new again. No more rough idle, full power is restored, and most importantly, no more smoke from the exhaust during acceleration. Had an emissions test done yesterday just to be sure, and the car passed with no issues. The malfunction is completely fixed and I am relieved I did not wait any longer, as the ventilation problem could have caused more expensive damage if left unchecked. Great to have the peace of mind back when driving.