Oil Pressure Gauge

I have a 2003 Suburban with around 38,000 miles. My oil pressure gauge is reading way past the maximum mark. I am assuming that the oil sending unit has gone out. Is this usually the first thing to go out or should I focus on something else first? Is there a way to test the oil sending unit?

Thanks

Just an update.

I ended up running the Suburban to the dealer and it was diagnosed as the instrument cluster going out and will be replaced shortly. This is not the first electrical problem that I have had with this vehicle.

What was the cost to replace the instrument cluster.

When you turned the engine off, would the needle go to where it normally should be with the engine running?