Found out code 51 means :
Cable from Tiller card is broken. Tiller card is bad. Plug to curtis controller has corrosion on pins. I removed the plug to inspect, found no corrosion, plug back into controller and unit started working good.

Ok ! Thank you.

just an update
all you can use is a curtis handset or the pc programmer software to access this control
that routine i described in my last post was for another model lift and will not work on this unit
sorry for the confusion, just wanted to tell you before you tried it

Thank you for the info. Will try it and see what happens. It is out of warranty, Yale has replaced the controller once already.

yeah this must be a fairly new truck and this 1232E series curtis controller i was assuming it was pretty much the same as the standard 1232 controller. Thats where i got my information from off of fsip's website. (flight systems). I'm taking a guess that it is probably very similar but probably has new features in it compared to the old model controller.
I would suggest that if this truck is in warranty to call yale and have them look at it.

Now as far as accessing the yale diagnostic if it is the same as the older units you just have to hold the horn trigger button and turn on the key and then release and pull the horn trigger button a couple of times real quick (within a couple seconds if i remember right), to get into the system. It will then make you go through a calibration routine with the control handle and then once complete you can navigate the menu system and find error codes and change settings, enable and disable functions etc.
Note: you will need the yale service literature for this though to get the correct parameters for it.

You can also use the latest version curtis handset or pc programmer software with special cable and do some programming in the controller itself but that is just motor controls, it is not truck model specific setup controls.
If by chance you cannot get it to allow you in then there may well be an issue with the controller and it might just have to be replaced.

Thank you for your reply. I can't seem to get any info. on this controller. I was thinking of replacing the Controller and see if it will fix it.

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.