Without “on board diagnostics” or not being able to duplicate the issue, it is impossible to fix without just replacing everything that is associated with the problem. Of course, that could be a lot of software and hardware so everybody associated with engineering maintenance and bean counting is very reluctant to help fix an issue. This applies to just about everything from a toaster to the space shuttle but touchscreens can be sensitive to numerous issues from the weather to human capacitance.
One of the reasons that touchscreens suck in just about every application except for, maybe, an iPad but especially for a car.