Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSMAZDA20086 S SPORT, 4D HATCHBACK, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 46 (ENGINE CONTROLS - SELF-DIAGNOSTICS)SYSTEM TESTSPOSITIVE CRANKCASE VENTILATION SYSTEM
2008 Mazda 6 s Sport, 4D Hatchback, Standard
Positive Crankcase Ventilation System
2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Positive Crankcase Ventilation System
WARNING: This page is about a different car, the 2002 Mazda B4000, 2002 Mazda B3000, and 2002 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
- Stuck PCV Valve Check
Turn ignition off. Verify PCV valve maintenance schedule has been performed. Remove PCV valve. Verify PCV valve is correct part number. Verify PCV valve is clean. Shake PCV valve. If PCV valve rattles when shaken, reinstall PCV valve. Go to next step. If PCV valve does not rattle when shaken, PCV valve is sticking. Replace faulty PCV valve. - PCV System Check
Start engine and idle until normal operating temperature is reached. Disconnect closure (fresh air) hose from remote air cleaner or air inlet tube (tube connecting mass air flow sensor and throttle body). Put a stiff piece of paper over hose end and observe. Wait one minute. If vacuum holds paper in place, PCV system is okay. Reconnect hose. See SYMPTOM DIAGNOSIS in TROUBLE SHOOTING - NO CODES article. If vacuum does not hold paper in place, system is leaking, plugged or EVAP system is leaking. Go to next step. - EVAP Emission System Check
If EVAP emission hose is not connected to PCV hose, perform no further action. Otherwise, disconnect EVAP emission hose at PCV hose connection (if equipped). Cap connector. Again, place a stiff piece of paper over closure (fresh air) hose end. Wait one minute. If vacuum holds paper in place, PCV system is okay. Go to 4 under DTC P0455 OR DTC P1443. If vacuum does not hold paper in place, check for vacuum leaks or obstruction in PCV system. Check oil cap, PCV valve, hoses, grommets, valve cover bolt torque and/or gasket leak. Repair as necessary.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.