Canon Printer Error E66 — What It Means & How to Fix It

What Does This Error Mean?

Error E66 on a Canon printer means the printer's internal temperature is too high. The printer has shut itself down as a safety measure to prevent overheating damage. This can be caused by heavy printing, poor ventilation, or a failing internal fan.

Affected Models

Canon PIXMA MG3600 Series
Canon PIXMA MG5700 Series
Canon PIXMA TS6300 Series
Canon imageCLASS MF240 Series
Canon PIXMA TR8500 Series

Common Causes

The printer was used for extended periods without rest, causing internal heat to build up
The printer is in a poorly ventilated space with insufficient airflow around it
The printer's internal cooling fan has failed or is running slowly
The ambient room temperature is very high, reducing the printer's ability to cool itself
Dust buildup inside the printer is blocking air vents and trapping heat

How to Fix It

Turn off the printer immediately. Unplug it and move it to a cooler, well-ventilated area if possible.

Allow at least 30 minutes for the printer to cool down before attempting to use it again.
Check the location of the printer. Ensure there is at least 6 inches of free space on all sides and behind the printer for air circulation.

Printers placed in enclosed shelves, cabinets, or corners with no airflow overheat much more easily.
Inspect the printer's air vents (usually on the sides and rear) for dust buildup. Use a can of compressed air to blow out any accumulated dust.

Dust acts as insulation and traps heat inside the printer. Even a thin layer of dust on the vents significantly reduces cooling efficiency.
After the printer has cooled, power it back on. If the error clears, run a test print and monitor the printer for any signs of overheating.

Consider printing in shorter bursts with rest periods in between if you regularly print large jobs.
If the error returns quickly after restart (before any significant printing), the internal fan has likely failed and needs replacement.

You can sometimes hear a working cooling fan running inside the printer. If you hear no fan noise during printing, the fan has failed.

When to Call a Professional

If the error persists after cooling down and improving ventilation, the internal fan may have failed. Fan replacement is an internal repair that requires partial disassembly. A Canon service technician can replace the fan and clean out accumulated dust at the same time.

Frequently Asked Questions

Is it safe to keep using the printer after E66 clears?

Yes, once the printer has cooled down and the error is gone, it is safe to use. However, if the overheating was caused by poor ventilation, the problem will keep recurring unless you fix the root cause. Consider repositioning the printer or reducing how many pages you print in one session.

How hot does a printer get inside?

Inkjet printers like Canon PIXMA models do not get as hot as laser printers — there is no fuser to worry about. However, the print head and electronics can still generate significant heat during extended printing. Most Canon inkjet printers are designed to operate in ambient temperatures between 15°C and 30°C (59°F to 86°F).

Can I prevent E66 from happening again?

Yes. Improve ventilation around the printer and avoid running very large print jobs without breaks. Keep the printer clean — vacuum or blow out the air vents every few months. If you live somewhere very hot, consider placing a small desk fan nearby during heavy printing sessions.