IIRR, if your getting the pressure switch error and NOT the low oil pressure warning, the switch could be stuck in the grounded position. Again, IIRR, the ECU checks to see if the switch is working. If it finds it showing pressure when the engine is not running, it will cause the error. It will also have an error if it stays showing no pressure when running, but then I think it throws the no oil pressure code and warning message as well.
Just some thoughts,
Tom
It should be a simple matter to check the switch with a multimeter
Without the engine running you would get continuity from the contact to chassis
While the engine is running you would get no continuity
Use a lamp wired from the battery, through lamp and grounded by the switch without engine running, should go out when started.