Some diagnostic codes don’t point directly to the component or system causing the engine performance issue. Using the scan tool to monitor live data, along with thorough visual inspection are the keys to a successful resolution.
Vehicle
2012 Opel/Vauxhall Mokka 1.4L Petrol
Title
P2270, P1101, Replaced Valve Cover
Complaint
The customer states the check engine light is on.
Cause
Connected a scan tool and found codes: P1101 – Intake Air Flow System Performance and P2270 – O2 Sensor Signal Biased/Stuck Lean (Bank 1 Sensor 2). Performed a road test with the scan tool connected, cleared the code, monitored the live data and found the short term and long term fuel trims were out of specifications. Performed a thorough inspection of the air intake system and found no apparent faults. With the engine running, removed the oil fill cap and found the pressure from the crankcase was excessive. Connected a smoke machine to the air intake system, induced smoke into the system and found when the oil fill cap was removed, smoke exited the valve cover opening. The positive crankcase ventilation valve assembly is integrated into the valve cover and is replaced as an entire unit. Removed the valve cover for inspection and found the positive crankcase ventilation valve was damaged. The results of these tests verified the valve cover was faulty.
Correction
Replaced the valve cover, cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.