Webnov 15, 2019 · chevrolet cruze eco is down again because of a p0171 engine code. Attributed to a failed pcv system. This video walks through the ultimate fix to the. Webthis condition may be caused by a missing non return valve. ⇒ increased crankcase pressure can force the oil into the induction system and eventually into the cylinders. Webaug 22, 2016 · pcv gas at the intake manifold check valve flows into the intake manifold but not back into the pcv system, and air at the turbo inlet housing…