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.
- 1) Check PCV Valve
Remove PCV valve. Shake valve and listen for rattle. If PCV valve rattles when shaken, install PCM valve and go to next step. Replace PCV valve if it does not rattle when shaken. - 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) Check Evaporative Emission System
Disconnect evaporative emission hose from PCV system and plug connector. Again, 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, proceed as follows:- On models equipped with Fuel Tank Pressure (FTP) sensor, go to CIRCUIT TEST HX , step 47).