I have a CAT S/N - A183F36127 & M/N - 2C6000. I've ran into an issue where the forklift with operate fine until it throws "E-31" and goes into a limp mode. Lift runs at half of normal operating speed. I've inspected wires to see if any were broken or loose, none were found. I have left work for the day and will be back again tomorrow. Any advice or opinions on what else to look at. I have a "Trouble Diagnosis" stack of papers, I will go through tomorrow. Any advice will help greatly, thank you in advance!