Its definitely the Oil Pressure Sensor. Had the same issue a few months ago on my 06 H2. Took about 30 minutes.
Its located on the top side if the back of the engine, between the firewall and the back of the intake manifold. Get a flashlight and you'll see it.
Use a 3/8" Drive 1-1/16" Deep well socket and a 6" extension. You have to move a few things out of the way to get to it but its definitely doable.
Here is a post with a picture of its location:
http://www.elcovaforums.com/forums/s...ad.php?t=41626