W-40
Epson Printer
Severity:What Does This Error Mean?
Warning W-40 on an Epson printer means the maintenance box is nearly full. The maintenance box (also called the waste ink pad) collects ink that is flushed out during cleaning cycles. This is a warning that the box needs to be replaced soon — before it fills up completely and locks the printer.
Affected Models
- Epson WorkForce Pro WF-4740
- Epson WorkForce Pro WF-5790
- Epson WorkForce Enterprise WF-C5790
- Epson EcoTank ET-4760
- Epson SureColor P400
Common Causes
- The printer has performed many automatic and manual cleaning cycles over its lifetime
- Heavy printing volume over time gradually filled the maintenance box
- The maintenance box was never replaced during the printer's service life
- Manual cleaning cycles were run too frequently, using more ink than necessary
- A cartridge was leaking ink internally, accelerating the fill rate
How to Fix It
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Identify the correct maintenance box for your Epson model. The part number is usually printed on the maintenance box itself or in the printer manual.
Common Epson maintenance box part numbers include T6711, C9345, and T04D1. Make sure you have the right one for your specific printer.
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You can continue printing after the W-40 warning — the printer is not locked yet. Order your replacement maintenance box promptly so you have it before the printer stops.
When the box reaches 100% full, the printer will display a harder error and refuse to print until the box is replaced.
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When the replacement box arrives, turn off the printer. Locate the maintenance box slot — usually on the rear or side of the printer.
Check your printer's manual for the exact location of the maintenance box on your specific model.
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Carefully remove the old maintenance box. It contains waste ink — keep it upright and place it in a sealed plastic bag for disposal.
Do not shake or tip the old maintenance box — the waste ink can spill and stain surfaces permanently.
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Insert the new maintenance box firmly into the slot until it clicks. Power the printer back on. The W-40 warning should clear automatically.
The printer reads the new box's chip automatically and resets the counter. No additional reset steps are needed.
When to Call a Professional
W-40 is a routine maintenance task you can handle yourself. Maintenance boxes are user-replaceable on most Epson printers — no technician required. Simply purchase the correct replacement box and swap it out.
Frequently Asked Questions
What is a maintenance box and why does it fill up?
The maintenance box (or waste ink pad) is a small container inside the printer that catches the ink flushed out during print head cleaning cycles. Every time the printer cleans the print head — automatically or manually — a small amount of ink is flushed out and absorbed by pads in the maintenance box. Over thousands of cleaning cycles, the box gradually fills up.
How often do I need to replace the maintenance box?
It depends entirely on how often you print and how many cleaning cycles have been run. For moderate home use, a maintenance box may last 2 to 5 years. For heavy office use with frequent cleaning cycles, it may need replacing every 1 to 2 years.
Can I reset the maintenance box counter instead of replacing the box?
Technically yes — some third-party tools can reset the counter. However, resetting the counter without replacing the physical box means the box will actually overflow without the printer knowing. Overflowing waste ink can spill inside the printer and permanently damage the main board. Always replace the physical box when you reset the counter.