Pathfinder 2000 SE 110K. The "Service Engin Soon" light comes on and goes off. I got it free checkup from local auto part store and the following "Nissan troble code P1491 Manufacturer Specfic Powertrain Trouble" showed up. I was told not to worry about it and the code was cleared free of charge. After week or so the light came back on, same results P1491. I however did some research and the following "CodeVacuum Cut Valve Bypass Valve" explanation given for P1491. Can any one please help me to understand this? Can I fix it my self? Thanks.

Here's a link to where the valve is located (this is on a 97, not sure if the 2000 is in the same spot): http://groups.msn.com/LewisPictures/shoebox.msnw?action=ShowPhoto&PhotoID=29

Check the harness for damage etc. To test remove the valve, when applying 12V to the two connectors the air passage should be open, no 12V and the air passage is closed.

Thanks, will try this solution.

Does any knows the location of "Vacuum Cut Valve Bypass Valve" for Nissan Pathfinder 2000 SE? Thanks!

Did you look where the diagram link above showed it? Maybe they moved it for the 2000.