It's very basic, I don't think there are thresholds, therefore it's only when a sensor goes open circuit it recognizes the fault, it's most likely a poor connection!

Apart from doing the basics and checking connections it can be tricky to pin point, given there is no logging!

The only exception is if you have a data stream, there is a output where you can connect a LED and a resistor, when an error occurs the LED flashes in a sequence to indicate what it is, but again given the fault is intermittent, you would have to have this connected at the point of failure!

Martin