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Service bulletin #PI0850A P0171, rough idle

#PI0850A P0171, rough idle, whistle Noise

Diagnose and fix P0171, rough idle, whistle noise

GM has issued service bulletin #PI0850A to address trouble code P0171, a rough idle and a whistle noise coming from the engine on the vehicles listed below

2011-2012 Chevrolet Cruze Equipped with 1.4L Engine (RPO LUJ)

P0171 symptoms

You may hear a whistle noise from the engine compartment and experience a rough idle, along with a check engine light and trouble code P0171. GM has determined the cause may be a vacuum leak in the positive crankcase ventilation (PCV) located on the valve cover. The PCV valve is an integral part of the valve cover. You must replace the valve cover to fix the problem. Note: The old style valve cover has a taller design PCV cap, while the new design has a flatter/lower cap.

To test, start the engine and place your finger over the breather port of the PCV diaphragm to see if the whistle noise goes away or the fuel trims are high then return to normal levels. If the noise goes away, replace the valve cover with the new design.


Old PCV valve cover design


New PCV valve cover design

55573746 Camshaft Cover

Posted on by Rick Muscoplat


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