Epson Printer Error Code E-91 — What It Means & How to Fix It

What Does This Error Mean?

The E-91 error on an Epson printer indicates a critical internal hardware or communication fault. The printer's self-test detected that one or more internal components are not responding correctly. This error prevents the printer from operating and usually requires professional service.

Affected Models

Epson EcoTank ET-2760
Epson EcoTank ET-4760
Epson WorkForce WF-3820
Epson WorkForce WF-4820
Select Epson inkjet printers

Common Causes

The main control board has detected a hardware failure in one of the internal subsystems
A communication breakdown between the main board and a component such as the print head or carriage motor
The printer firmware has a critical bug that is causing a self-test failure
A component failure occurred during a print job and left the printer in an error state
The power supply is not delivering stable voltage, causing internal component errors

How to Fix It

Power off the printer and unplug it from the wall.

Wait at least 2 minutes. Then plug back in and power on. A full power reset sometimes clears transient errors.
Check that the printer is plugged directly into a wall outlet — not a power strip or UPS.

Some power strips deliver unstable voltage that can cause internal component errors. Try a different outlet.
Open all access panels and check for paper jams or foreign objects.

A stuck piece of paper or object can cause mechanical errors that the printer reports as E-91.
Check if the printer has a firmware update available.

Visit epson.com/support, enter your model number, and check the Software / Firmware section. Install any available updates.
If the error persists after all steps, contact Epson support.

Note your printer's model number, serial number, and when the error first appeared. This helps Epson diagnose the issue faster.

When to Call a Professional

E-91 almost always requires professional repair. Epson's authorized service centers have the diagnostic tools to identify the exact failing component. Contact Epson support at epson.com/support or call 1-800-463-7766. For printers still under warranty, Epson may repair or replace the unit at no cost.

Frequently Asked Questions

Is E-91 covered under Epson's warranty?

If your printer is within the 1-year standard warranty period, Epson will repair or replace it at no charge. Check your purchase date and keep your proof of purchase. Contact Epson support and provide the serial number — they can look up the warranty status. Epson's extended warranty (if purchased) also covers this type of hardware fault.

Why did my Epson printer suddenly show E-91 without any warning?

Internal component failures can happen without warning, just like any electronic device. A power surge, aging component, or manufacturing defect can cause a sudden failure. In some cases, a firmware bug causes the printer to incorrectly report E-91 even though hardware is fine — a firmware update can fix this.

Can I fix E-91 at home?

In most cases, no. E-91 indicates a deep internal fault that home users cannot diagnose or repair without specialized tools. The best first step is a full power reset. If that doesn't work, contact Epson support — do not attempt to open or repair the printer yourself as this will void the warranty.