2500HD 8.1 liter

I have 2004 2500HD 8.1 liter that shows no oil psi, but computer has sent warning and engine is cool and running fine. Can some one help?

I made mistake....computer has NOT shown warning
 

It maybe the gauge, some of those years around yours had a service bulletin put out to extend the warranty of the gauges to cover the defects. Read this post, http://www.chevroletforum.com/m_24024/tm.htm 

it very well could be a gauge, it also very well cold be a connection at the gauge. just make sure that there is oil in it cz the 8.1 liter is known for burning oil even when new. i got 67000+ on mine it burns about a quart every 1600 miles or so. but if the compter does not send a message then the sensor is obviously working.