When Error 1901 becomes active, the forklift will typically exhibit one or more of the following behaviors:

. The system should reset, and the error code should disappear. 2. Inspect the Accelerator Pedal Assembly

| Code | Meaning | Recommended Action | | :--- | :--- | :--- | | | No travel direction selected when accelerator pedal applied. | Before pressing the accelerator, ensure you have selected Forward or Reverse with the travel switch. | | 1908 | Seat switch not closed; truck operational but driver's seat not occupied. | The forklift may operate but at a reduced speed. Ensure you are properly seated so the switch is activated. The truck will not move if you are not in the seat. | | 1909 | Accelerator pressed while parking brake applied. | Release the parking brake before pressing the accelerator pedal. | | 1917 | Accelerator pedal and brake pedal pressed simultaneously. | Avoid pressing both pedals at the same time. Use only the appropriate pedal for your intended action. | | 2951 | Hydraulic function applied during power-up. | At startup, ensure no hydraulic levers (e.g., lift/lower/tilt controls) are being activated. |

If paired with 1900, your motor may truly be overheating.

While the base code indicates the accelerator pedal was pressed, it can appear with different sub-index numbers, which provide more specific diagnostic information.

Ensure the parking brake is fully released (Error 1909.1 is also related to pedal activation while the brake is engaged).

The acceleration pedal (either forward or reverse) is pressed.

Several factors can lead to this error, ranging from simple operator error to mechanical or electrical failures:

Here are the steps to troubleshoot and resolve the Jungheinrich error 1901, ordered from simplest to most complex. 1. The "Reset" Approach (Check Operator Error)

Reconnect the sensor. Turn on the key (traction active). Measure DC voltage between the two sensor wires at the controller side:

Electric forklifts require highly stable voltage to process logic commands. If a battery cell is dying, or if the main battery plug has high resistance due to burning or corrosion, the voltage supplied to the controller can drop sharply under load. This sudden voltage dip confuses the logic processor, resulting in an internal controller error. 3. Faulty or Corrupted Controller Hardware