I would recommend against doing active development with the 5.6 API. The 5.6 API is being retired and only legacy servers are being held on version 5.6 until their current integration has been upgraded to 5.7. I would strongly recommend you work with your reseller to find more information about the deadline for 5.6 servers.
Accelerometer data is recorded as StatusData. Searching for status data with the desired diagnostic, in the dates of the event should provide the data you are interested. A rule's condition tree would have the information of which diagnostic (if any) the exception event was generated for. An easy way to check the conditions is to view them in MyGeotab by navigating to the Rules page, clicking the rule, it's condition tab, then the far right button "Show the advanced conditions editor".