Jungheinrich Error Code 1901 __link__ File

Jungheinrich Error Code 1901 indicates that the drive pedal was activated during truck startup. This is a safety failsafe designed to prevent the industrial truck from moving abruptly when the key is turned or the system is energized. 📋 Incident Report: Fault Code 1901 1. Error Identification Error Code: 1901 (often displayed as E1901 or 1901.1). System Classification: Operator Error / Startup Interlock. Affected Component: Traction Control System / Drive Pedal.

Meaning: The system detected a closed drive pedal circuit (acceleration requested) at the exact moment the truck was switched on. 2. Potential Causes

Operator Behavior: Stepping on the accelerator pedal before or while turning the ignition key.

Mechanical Obstruction: Debris or a floor mat physically jamming the pedal in a depressed position.

Sensor / Switch Failure: A short circuit or mechanical failure in the pedal position sensor or microswitch, signaling that the pedal is depressed when it is not. Jungheinrich Error Code 1901

Wiring Fault: Damaged or shorted harness wires sending a false voltage signal to the controller. 3. Operational Impact

Traction Lockout: The truck's main contactor may refuse to engage, preventing any travel.

Safety Hold: The unit will remain immobilized until the active signal at startup is cleared and the startup sequence is properly recycled. 4. Corrective Action Plan Step 1: Turn the truck completely off.

Step 2: Ensure the operator's feet are completely clear of the drive pedal. Jungheinrich Error Code 1901 indicates that the drive

Step 3: Visually inspect the pedal to ensure it has fully returned to its neutral, resting position and is not physically blocked. Step 4: Turn the truck back on. 🛠️ Advanced Technical Troubleshooting

If the error persists after recycling the power without touching the pedal, follow these diagnostic steps:

Physical Pedal Return: Verify that the return spring is not broken and successfully pulls the pedal back to zero.

Wiring Harness Check: Inspect the wiring routed from the pedal assembly to the traction controller for pinched, exposed, or shorted wires. Expected range: 0

Sensor Calibration: Use the Jungheinrich diagnostic software (JET) to check the zero-point voltage of the drive pedal. If it rests outside the mapped tolerance, it will trigger a false activation at startup. Jungheinrich error code 1901

Step 5: Measure Controller Input Voltage (Reconnected)

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

• Expected range: 0.5V – 4.5V depending on motor temperature.
• If voltage is stuck at 0V → short to ground.
• If voltage is stuck at 5V → open circuit.

Method 3 – Emergency Bypass (Not Recommended, Temporary Only)

Warning: This is for moving the truck a few meters onto a trailer or out of an aisle. Do not operate normally. Some older Jungheinrich models (pre-2015) allow a temporary override:

• Locate the drive controller service jumper (a small two-pin plug near the main connector). Short it with a paper clip (on specific models like the ETV 110-216) to force the controller into “Standalone Mode.” This ignores CAN communication but disables all safety features (e.g., speed limiting, tilt interlocks).

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.

Method 2 – Diagnostic Tool Reset (JMA or Jungheinrich Service Tester)

This is the preferred method.

1. Connect the service tester to the 9-pin or 14-pin diagnostic socket.
2. Navigate to Fault Memory > Drive Controller > Read Errors.
3. Select Error 1901.
4. Choose Clear / Reset Error.
5. Cycle the key off and on.
6. Perform a “teach-in” or “calibration” of the drive controller if prompted (this relearns accelerator pedal and encoder limits).

When to call service

• Code persists after visual wiring checks, power cycle, and fuse/ground verification.
• Multiple communication nodes failing or intermittent errors.
• You lack the Jungheinrich diagnostic tool, firmware access, or certified replacement modules.