Diagnostic Aids

Perform this test when instructed during QUICK TEST  or if directed by other test procedures. Use this test to diagnose Positive Crankcase Ventilation (PCV) valve and related vacuum hoses.

Fig 1: PCV System Schematic

1. Step 1) Check PCV Valve  Remove PCV valve. Shake valve and listen for rattle. If PCV valve rattles when shaken, go to next step. Replace PCV valve if it does not rattle when shaken.
2. Step 2) Check PCV System  Start engine and warm to normal operating temperature. Disconnect hose from remote air cleaner or outlet tube. Place a stiff piece of paper over end of hose. If vacuum from hose does not hold paper in place for one minute, go to next step. If vacuum from hose holds paper in place for one minute, PCV system is okay and testing is complete.
3. Step 3) Check Evaporative Emission System  Disconnect evaporative emission hose from PCV system and plug connector. Place a stiff piece of paper over end of hose. If vacuum from hose does not hold paper in place for one minute, isolate vacuum leak or restriction and repair as necessary. If vacuum from hose holds paper in place for one minute, go to CIRCUIT TEST HV.