A while ago there was a fix to install a resistor to get rid of certain errors. Something to do with discharge temp error. My recommendation is to call Manitowoc to see if the 50K resistor still applies.
This is a guest, so I doubt he will see our answers to his problem. But, there is no t4 error code. are you getting a E024? and do you have a build date or serial? Has the software ever been updated? In the troubleshooting menu, what does it show for your delta T (T3 – T4). T4 is the evaporator discharge. T3 is the evaporator inlet. It would help if we had the actual reason for service in the first place. .