2001 Pathfinder

I am new to this forum. I've been reading for couple of days, find it very informative. Here's my problem. I have a 2001 Pathfinder SE. SES light has been on for couple of weeks. Scanner code is P1140. This is a manufactuer specific code. As best as I can see this code refers to the intake valve timing sensor left hand bank 1. Does anyone know if this is correct? If not, what is the correct interpretation? If yes, what and where is it? How can I replace it? What is the approximate cost? I am due to turn in from lease in a month, but would like to clear it up soon. I can't bear to take it to the dealer if this is not a big deal. Thanks for the help.

wrong forum...this is the Altima forum.