Oil Pressure light reads H all the time

It just happened today, I looked down at the oil pressure light and it read H the entire time I drove home. The vehicle was warmed up to operating temp. I checked the oil level, and everything was within range. I tried to call the service dept. for an appointment but got their voicemail. Customer service at its finest, I guess that is what happens when you buy two new Nissans ( Armada & Murano ). Luckily the Murano has been ok. Any input as to the problem would be helpful.