Hello, forklift still does not cooperate after a few days of testing. Anyone have an idea what might have happened? the inverter is broken or does the potentiometer just need to be calibrated by the handset? I will add that the error appeared while driving in a cold store (it drives in normal conditions on a daily basis)

Thanks for the information. Earlier, I changed the potentiometer and set it with an ohmmeter in the middle and the error 28 (KO steer sensor) was still displayed. The wires from the potentiometer to the inverter are good. In addition, the forklift has a limited speed (as if it were riding a turtle) and the microswitch does not activate the second and third sections of the control valve (the wires are also good). I wonder if the forklift will behave like this if it is in safe mode. Maybe the inverter zapi logic broken?

in a pinch, you can manually calibrate if you cant access dash. First, you needed to really center the steer wheel. With an ohmmeter, get pot centered as best you can. this gets you pretty close. With drive tires in air, run in forward then steer all the way left. Left wheel should stop or turn in reverse. Do right...if same you're good to go. If you are not centered, a hard turn may force the inside wheel to aggressively turn. This can blow a controller.
this adjustment depends on how EASY the steer pot is to access. Last Hyundai i did needed counter weight removed! I did adjustment manually as i could not access calibration settings