that code refers to the ACCESS 4 CASTER BRAKE (BRK2) COIL OPEN CIRCUIT.
one of the wires to the BRK2 outer coil has an open circuit. The current <0.5 A. Use ANALYZER MENU/ A3.4.20.3 to monitor the BRK2 resistance and A3.4.20.2 to monitor the current feedback.

(turn the truck OFF. disconnect ACCESS 4 CA411. Measure the resistance from ACCESS 4 CA414-34 ti CA411-35)

IF; the resistance is >8 ohms
then there is damage to the wire or connector. check the connector pins for corrosion. make the necessary repairs or replacements.

IF: there is an open circuit.
then make the necessary repairs or replacements

IF: the wires and connections are good/ok
then replace BRK2 coil

hope this helps.