It should have two sensors, one right above the oil filter that runs the gauge and a smaller one further back on the block that runs the warning light. I wouldn't trust either of them completely, could be the light sensor is reading lower than it should (clogged or just bad) or the gauge sensor is reading higher than it should. It might be that there is a clogged passage somewhere between the two or something like that that explains the difference. Only way to be sure is to hook up another gauge, preferably mechanical and verify the actual pressure.

"Time and tide melts the snowman"