would this be an alarm 35 on mod 2?
this has to do with low battery voltage.
a service gram was sent out by MCFA about this alarm involving the alarm code on all mods and including the K2 contactor and some troubleshooting that needs to be done to help remedy the problem.

The technician should check loaded battery voltage. The battery should be thoroughly check for, but not limited to: proper water level, loose battery connection, corrosion, etc....
It's recommended using a fully charged battery to troubleshoot the truck.

now the alarm 35 indicates low battery voltage scenario,
the mod indicates the module or models experiencing this problem. Mod 2 is the traction controller.
Here is a list of how they are arranged on the truck:
Model 1 = SICOS/Display Unit Controller
(SICOS)
Model 2 = Traction Controller (AC2)
Model 5 = Pump Controller (AC2)
Model 6 = Electric Steer Controller (EPS)
Model 9 = Hydraulic Controller (MHYRIO)
Model 37= Pump Controller (AC3)

The 8volt loss at the K2 is a sign there is a problem, the voltage variance should not be more than 1 volt.

now at the end of the troubleshooting in this service gram they do have a note that if once the battery and K2 contactor are verified to be good, to call service engineering.
My guess is there is a problem inside the controller and they will probably have the unit replaced since they are not serviceable internally.

Now i do find it odd that flight systems would not look at this controller being it is a zapi controller and they do provide reman and rebuilt exchange ones on their site. Is there another reason why they would not deal with you on this? Very strange indeed.