Hi did you fix problem? I remember fighting with same error code. Problem was truck runs ok but after a few minutes suddlendly stop working. Board dc-sdd was the issue. One of the pcb board tracks were affected by corrossion and sometimes one of the resistors inside the board was doing good contact and then truck start working again.

Its a real headache to fight with old controllers. Are quite good, but when components and boards are exposed to corrosion or sulphatation you can get intermittent issues really difficult to repair.