Case Study: Chevrolet Cruze Limited check engine light on

Vehicle: 2016 Chevrolet Cruze Limited LT 1.4: 

Problem: Customer states that the check engine light is on.

Case details: The technician connected a scan tool and found codes: P0106 – manifold absolute pressure (MAP) sensor performance; P015B – O2 sensor delayed response – lean to rich (bank 1 sensor 1); P0171 – system too lean (bank 1), and P1101 – intake air flow system performance. With the scan tool connected, the technician cleared the codes, performed a road test, monitored the live data, and found that the long-term and short-term fuel trims were out of specifications.

Then a visual inspection was performed of the air intake system and no apparent faults were found. A smoke machine was connected to the air intake system and found a leak. The engine oil fill cap was removed and it was found that smoke leaked from the valve cover. After removing the valve cover for inspection and the technician found that the positive crankcase ventilation (PCV) valve was damaged.

Confirmed repair: To fix this problem, the technician replaced the valve cover, cleared codes, performed a road test, and verified the vehicle operated properly. After this, the check engine light did not illuminate and no fault codes returned.

Reprinted with permission from SureTrack, a value-added feature available with select Snap-on diagnostics tools.