Transmission Problem Codes on 2002 Jeep Grand Cherokee

My Jeep just developed a transmission problem and my local gas station checked the computer codes because my "Check
Engine" ligh had come on.
The codes indicate: 1. Governor Press Sensor above 3 PSI in Gear with Zero MPH.
and 2. Governor Press Sensor Off-Set Volts Too Low or Too High.
What does this mean and is it a costly problem to repair?

Asked by for the 2002 Jeep Grand Cherokee
I had the governor sensor changed in the transmission at the dealership it cost 300 plus dollars but haven't had any problem since.
1 more answer
I have found there to be lots of problems with the Jeep Tranny. I have had to replace the entire electronic valve bodies on many Jeeps that have these types of codes. Best thing to to do is to go to an ATARCO certified trans shop and have one of their diagnostic techs check out the problem. Maybe it is only a pressure sensor ( much cheaper )