Twingo Crankcase Ventilation Issue

Those symptoms do point to a potential crankcase ventilation system problem. A malfunctioning valve can cause the check engine light, reduced performance, and smoke. The pressure buildup can force oil past seals. Have you checked the engine oil level recently? Any change in the oil's consistency or color?

I did check the oil level and saw a slight decrease, but nothing too alarming. The consistency and color looked normal. If it's the crankcase ventilation valve, could this also affect emissions? Is it safe to drive, or should I wait until it's fixed?

Given the symptoms and your findings, a defective crankcase ventilation is likely the cause. It can affect emissions. Driving it could cause further complications, like damage to seals and increased engine wear. I suggest getting it inspected by a mechanic for diagnosis and repair.

Thanks for the help. I scheduled an appointment, and the mechanic confirmed the crankcase ventilation valve was defective and needed replacement. The repair cost 360€ including parts and labor. Thanks again for the guidance.