Jungheinrich Error Code 1901

Here is the explanation for the Jungheinrich Error Code 1901 and its associated feature.

Error Code 1901 typically indicates a communication fault between the traction controller and the hydraulic controller (or main control unit) on the CAN bus network.

Does Error 1901 appear on both AC and DC motors?

Yes, but far more common on AC drive motors (3-phase) because they use smaller, more sensitive NTC sensors embedded directly in the copper windings.

Preventative Measures

To minimize the occurrence of Error Code 1901 and other issues: Jungheinrich Error Code 1901

• Regular Maintenance: Regularly inspect and maintain the machine's hydraulic and electrical systems.

• Training: Ensure that operators are properly trained to use the machine and recognize early signs of potential problems.

• Scheduled Servicing: Adhere to the recommended servicing schedule provided by Jungheinrich. Here is the explanation for the Jungheinrich Error

Repair Recommendation

• If wiring/connectors are OK → Replace the traction controller (part number varies by model – check truck serial number).
• If water damage is visible → Replace controller and protect new unit with dielectric grease and sealed cover.

⚠️ Safety note: Always disconnect the battery before unplugging controllers. Capacitors in the drive controller can hold dangerous voltage for up to 5 minutes after key-off.

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If error 1901 appears after controller replacement, perform a "CAN bus reset" via the service menu (Code 5 – CAN Reset).

How to Reset Jungheinrich Error Code 1901

Important: Simply clearing the code without fixing the root cause will cause it to return, possibly within minutes. Use the following reset methods only after performing the troubleshooting steps above. Training: Ensure that operators are properly trained to

Data to provide to service technician

• Vehicle model and serial number
• Battery voltage and state
• Exact error code(s), timestamps, and conditions when occurred
• Results of quick checks and diagnostics performed
• Photos of connectors, wiring, and modules if possible

Step 3 – Isolate the Drive Controller

• Disconnect the CAN bus connector from the drive controller.
• Check if Error 1901 changes to another code (e.g., 1902 – missing node).
• If the error persists with the controller disconnected, the main controller or wiring is faulty.
• If the error disappears (but other CAN errors appear), the drive controller itself is likely defective.

Cost Implications of Ignoring Error 1901

Ignoring this error or repeatedly resetting it without repair leads to:

• Downtime: Average repair delay of 4-6 hours if parts are on hand; up to 5 days if a controller must be ordered and programmed.
• Secondary Damage: A failing drive controller can send voltage spikes back into the CAN bus, destroying the main vehicle control unit (MCU) – a $2,000–$4,000 repair.
• Safety Risk: Loss of traction while carrying a load on a ramp or incline could cause tip-overs, product damage, or injury.

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Fix #4: Replace Traction Controller (rare, expensive)

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.