Hello again vsaks :oD
code 44 eh?
well first off i would check the battery voltage and make sure it is charged up full.
36v battery i presume? it should be reading about 37.5 to 38v (if new it will be higher). You can check each cell and they should be close to 2.14v at 100% charge with no more than a 0.02v variance between cells.
as for the code the troubleshooting code chart says:
PC Contactor detected closed when it should be open.
Possible Causes:
1-Defective PC coil driver
2-Welded PC contactor tips
3-Binding contactor plunger
4-Defective return spring
5-Bad contactor panel harness
6-The Vehicle Manager may be bad
7-The PC Sense circuit may be defective
8-The PC Sense line (JPF2-9) may be shorted to B+
9-Circuitry related to the PC Sense line on either the Power Panel Driver Assembly, distribution board, or the VFC may be bad.

I would check that contactor real good and make sure the tips are good, not welded and make sure the movable part is not worn and binding up. You can clean it up with some contact cleaner and blow it off dry, dirt can cause binding.
One way to check the wiring circuit is to run tests:
O00 and A00. Those are in the maintenance menu section after you access the onboard VCM.
The coil drivers are on a small circuit board on top of the control panel area behind the cover on the RH side of the operator compartment where the contactors and VCM are. They are all identical so you can swap them around to see if the problem moves to another code, if it does then one of those driver modules is bad. That's actually what the tblshooting manual says to do haha.

The PC contactor is the one on the top right corner of the panel just to the right of the large main fuses.