901B4602

Error 901 OKI B4602: Main motor failure

The OKI B4602 error 901 is a warning indicating an irregularity in the printer's main drive motor. This failure usually happens when the system detects excessive mechanical resistance that prevents the drum or transport mechanism from rotating correctly. If your OKI B4602 shows error 901, it is likely that an internal component is jammed or requires technical lubrication.

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Common causes

  • 1Physical obstruction by paper scraps in the transport guide.
  • 2Premature wear of the main motor bushings.
  • 3Accumulation of residual toner in mechanical gears.
  • 4Motor synchronization sensor failure.

Solutions

Quick Diagnosis

If you hear clicking or forced humming sounds just before the error 901 appears, it is an unmistakable sign of a mechanical jam in the paper path.

Step-by-Step Solution

  1. Switch off the unit and visually check that no gears are jammed by paper.
  2. Remove the toner and image unit to see if the motor spins freely without obstructions.
  3. Turn the printer back on to try and calibrate the motor cycle.
  4. Ensure no foreign particles or staples are near the rollers.

Prevention and Maintenance

Avoid using adhesive labels not suitable for laser printers, as they can peel off and jam the motors. Clean the interior with compressed air every 6 months to remove paper dust that overloads the motor.

When to Call a Technician

If the motor still does not spin after removing the consumables or if the metallic noise persists, error 901 indicates a stepper motor failure that requires professional replacement.

Technical Specifications

  • Technology: Monochrome laser printer
  • Mechanism: Main drive motor
  • Monthly Cycle: Up to 50,000 pages
  • Consumable: B4600 series toner
  • Connectivity: USB / Network
  • Official drivers / firmware

Steps to follow

  1. 1

    Gear inspection

    Switch off the unit and visually check that no gears are jammed by paper.

  2. 2

    Load test

    Remove the toner and image unit to see if the motor spins freely.

  3. 3

    Mechanical reset

    Turn the printer back on to try and calibrate the motor cycle.