Well the tick and the winking light are two indicators of very low pressure so I don't think I'd trust your gauge if it reads 40# at the same time. Has the bottom of the pan been scraped on anything lately that may have bent it against the pick up? I think you're on the right track, you could remove the plug on the oil pump where the bypass valve is and check that out, probably wouldn't hurt to just remove the whole pump and check it out.