Volvo ECR305CL in limp mode

Hi HEF, I have a Volvo ECR305CL which runs in a limp mode of sorts. It tracks slow and the arms move slowly, but it will return to its normal speed when the controls are wiggled around. The wiring harness experienced some damage from a broken muffler leaking heat onto the wiring harness, and that muffler was recently repaired. The wiring which was damaged was also spliced and repaired. Still, the machine limps. Volvo dealer techs have tried their best to get computers to communicate with the machine to no avail. It's a strong machine otherwise, but if we can figure out how to get out of this limp mode without a full wiring harness replacement, it would be a huge help. Any ideas? --Alex