The cable from the drive motor to the controller runs through a flexible link (especially on reach trucks with moving masts). Constant flexing breaks internal copper strands.
Overview On Jungheinrich forklifts and material handling equipment, Error Code 1901 typically indicates a hardware communication fault, specifically related to the vehicle's Controller Area Network (CAN-Bus) system. Jungheinrich Error Code 1901
In most modern Jungheinrich machines (especially EFG and EJE series), this code signals that a specific control module—usually the Vehicle Controller (VE)—has lost communication with another major component, such as the display interface or a peripheral sensor module. The cable from the drive motor to the
The CAN bus uses a twisted pair of wires (typically CAN High and CAN Low, often colored orange or yellow in Jungheinrich harnesses). If these wires are chafed, partially cut, or loosely connected at the controller’s 12-pin or 35-pin connector, intermittency occurs. The CAN bus uses a twisted pair of
Only do this if you have confirmed good sensor, good wiring, and the controller still reads 5V fixed at its input. A used SEM controller can cost $800–$1500. Reprogramming via Jungheinrich dealer is mandatory.