The potentiometer (which sends the signal of how far the pedal is pushed) might be faulty or sending a false signal, telling the system it is "active" when it is not.
This is a safety-oriented fault code. The forklift's electronic system expects to see the travel pedal (accelerator) in the "neutral" or "zero" position when the machine is first turned on or when the operator attempts to activate the lift. If the pedal is pressed down during this initiation sequence, the system throws an error to prevent unexpected movement. Causes of Error Code 1901
According to Jungheinrich's official operating manuals for various models, Error 1901 has a consistent and straightforward definition:
using the key switch or disconnect the emergency stop button. Jungheinrich Error Code 1901
The causes of Error Code 1901 can be multifaceted. Some common reasons include:
Jungheinrich Forklift Error Codes - Machine Maxx USA. * 0915.2 – Industrial truck not ready for operation – battery door opened. * Machine Maxx USA Jungheinrich Forklift Truck Fault Codes DTC.pdf
Troubleshooting Error Code 1901 requires a systematic approach: The potentiometer (which sends the signal of how
This guide is for informational and basic troubleshooting purposes only. It is not a substitute for the official Jungheinrich service manual for your specific model. Always refer to the manufacturer's documentation and follow all safety procedures. For persistent issues or if you are unsure of any step, contact a certified Jungheinrich service professional.
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: The truck's controller has detected that the accelerator (drive pedal) is not in its neutral position while the key switch is being turned or the system is booting up. Safety Function If the pedal is pressed down during this
Either the wiring fault is intermittent (false hope) or the sensor resistance is borderline – fine at startup but drifts out of range when warm.
The electrical "zero point" calibration can drift over thousands of operational hours. The controller then misinterprets a fully released pedal as slightly pressed.
