If i determined this correctly according to the model number you posted this is a curtis controller? It is of the model 1232 series.
According to curtis service literature on this model these flash codes are translated as follows:
red led will flash a 1 or 2 indicating if there is a code to follow the current displayed code, 1 flash should mean there will be one to follow, and 2 flashes indicating the end of the code.
The yellow led flashes the actual error code digit which is generally a 2 digit code according to curtis's information.
If this follows most protocols it would pause at that point and either repeat the same code or if there are multiple codes stored it will begin the next code in the same manner.

Now according to your description the yellow flash is the actual error code so based on how you described it the error code would be a 51.
According to the code list in this models service literature codes 51-67 are OEM specific so the yale service literature on this model would be a specific error as defined by the OEM VCL code flashed into the controller.
Being the display is showing FLT30106 CAM COMM this would be some sort of communication error. As to specifically what it refer's to i am going to assume is internal to the controller.
I do not have a specific service book on this newer VGN model yale truck so at this point i cannot elaborate any further other than the general curtis information i have come across at this point. If i can find anything else i will come back and update my post.
Or maybe someone else on the forum that has this information can answer more specifically what code 51 is and how to check the controller and what the suggestions are.