e-04EcoTank L120

Epson EcoTank L120 Error e-04: Connection Fault

The Epson EcoTank L120 error e-04 is a communication fault message indicating that the host computer cannot communicate with the printer. Users searching why does Epson EcoTank L120 show error e-04 usually encounter hardware faults with cables or outdated software. This guide helps you identify and resolve these connectivity hurdles.

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Common causes

  • 1Frayed or low-quality USB cable.
  • 2Outdated or corrupt printer drivers.
  • 3Faulty computer USB port.
  • 4Queue conflict in the OS.

Solutions

Quick Diagnosis

If your computer does not react when the printer is connected, the issue is almost certainly the physical USB cable or the USB port itself.

Step-by-step Solution

  1. Disconnect printer.
  2. Swap USB cable.
  3. Reinstall driver software.
  4. Reboot PC.

Prevention and Maintenance

Use certified USB 2.0 cables. Avoid extending the cable, as length causes signal dropouts. Keep ports free of dust.

When to Call a Professional

If the printer is not recognized by any computer, the printer's mainboard internal USB controller may be faulty.

Equipment Specs

  • Technology: Inkjet.
  • Speed: 27 ppm.
  • Consumable: T664.
  • Usage: Home.
  • Drivers

Steps to follow

  1. 1

    Inspect USB Cable

    Unplug the USB cable and reconnect it to a different port on the computer.

  2. 2

    Refresh Drivers

    Uninstall the current driver and download the latest version from Epson’s official support site.

  3. 3

    Device Status

    Check your system’s Device Manager to see if the printer is flagged as unknown or faulty.

Frequently asked questions

The printer is unable to establish or maintain a stable communication path with the connected host computer.

Yes, cables often fail. Testing with a different, short USB cable is the first diagnostic step.

Only use Epson-provided drivers to avoid software conflicts with your system.

Rebooting both the computer and the printer clears temporary connection locks.