I know the Cabrio F6E2 error is a communication error but how do I troubleshoot and fix the problem.
Yes you are correct the F6E2 is a communication error: Fault is displayed when communication between the UI and the ACU has not been detected. First thing you want to do is check all the wiring between the user interface board and the main control board. Make sure the wiring is not loose, broken, burned etc; Check the wiring with a meter for continuity. If the wiring checks out then you will want to do test #1 on page 14 and test# 4 on page 17 as listed on the tech sheet I have provided below:
Click here to download technical data sheet