Canon Printer Error Code 4000 — What It Means & How to Fix It

What Does This Error Mean?

Canon error 4000 is a scanner or document communication fault. It usually means the printer-scanner combination (multifunction printer) was asked to scan but could not complete the operation. This can be caused by a connection issue, incorrect software settings, or a scanner hardware problem.

Affected Models

Canon PIXMA MG3620
Canon PIXMA MG5720
Canon MAXIFY MB5420
Canon PIXMA TR8520
Canon imageCLASS MF236n

Common Causes

The Canon scanning software on your computer lost its connection to the printer mid-scan
The document was moved or removed from the scanner glass before the scan completed
The scanner lid was opened during a scan, interrupting the light sensor
The USB or network connection dropped while the scanner was transferring image data to the computer
A software conflict or outdated scanner driver is preventing the scan from completing

How to Fix It

Cancel the current scan job on both the printer panel and the scanning software on your computer. Then restart the printer.

An interrupted or stuck scan job can block new scan attempts until it is fully cleared.
Check the connection between the printer and your computer. If using Wi-Fi, ensure the printer is on the same network as the computer. If using USB, check that the cable is firmly connected at both ends.

Scans require a stable, continuous connection because image data is much larger than text print jobs. Even a brief dropout can trigger error 4000.
Open the scanner lid and clean the glass with a soft lint-free cloth. Make sure there are no documents, clips, or debris on the glass or hinge area.

Small objects caught in the scanner hinge can prevent the lid from closing fully, which some Canon models detect and block scanning.
On your computer, open Device Manager (Windows) and look under Imaging Devices. If your Canon scanner shows a warning icon, right-click it and select 'Update driver'.

On Mac, go to System Preferences > Printers & Scanners, remove the printer, then add it again to refresh the driver.
Uninstall the Canon scanning software completely using Add/Remove Programs, then download and reinstall the latest version from Canon's website for your specific model.

A clean reinstall resolves driver conflicts that accumulate over Windows and macOS updates.

When to Call a Professional

If error 4000 occurs on every scan attempt — even when the connection and software are correct — the scanner's CIS (Contact Image Sensor) may be damaged or dirty beyond surface cleaning. A Canon service technician can inspect and replace the scanner unit. For entry-level PIXMA models, the cost of repair may approach the cost of a new printer.

Frequently Asked Questions

Why does my Canon printer print fine but fail when scanning?

Printing and scanning are handled by different components and different software drivers. The printer driver manages print jobs, while the scanner driver (usually called ICA or WIA driver) handles scans. A problem with one does not necessarily affect the other — you may have a perfectly working print driver but a corrupt scanner driver.

Can I scan wirelessly, or does error 4000 require a USB connection?

Canon PIXMA and MAXIFY multifunction printers fully support wireless scanning. If wireless scanning triggers error 4000 but USB scanning works, the problem is the network connection — not the scanner itself. Check that the printer has a strong, stable Wi-Fi connection before scanning wirelessly.

Error 4000 appeared while using a third-party scanning app. Is Canon's own app different?

Yes, and it matters. Third-party apps like Windows Fax and Scan or VueScan may not handle Canon-specific error codes the same way. Try scanning using Canon's own IJ Scan Utility first. If it works there but not in the third-party app, the issue is the app's compatibility with your printer model, not the printer itself.