Canon Support Code 6803 — “Internal temperature is high” safe reset & cooling guide

Joe B.

Reviewed for technical accuracy

Specialities: Canon PIXMA/MAXIFY, MegaTank, thermal inkjet print heads, paper path, power & cooling issues

Canon Support Code 6803 “internal temperature high” — overheating, blocked vents, sensor faults explained

Technician

Hey! We’ll walk through a safe, step-by-step fix for Canon Support Code 6803, which usually means the printer reports an internal temperature is high condition.
Before we do anything: power the printer OFF using the button (don’t yank the cord yet), let any movement stop, and then unplug it from the wall. This protects the thermal inkjet print head and power supply.
A few quick questions so I can target the right solution: Which Canon PIXMA / MAXIFY / G-series MegaTank model is this? Is the printer in a tight cabinet or near a heat source? And did Support Code 6803 appear during long print runs, after a jam, or immediately at startup?

Customer

It’s a Canon PIXMA G-series MegaTank. The 6803 internal temperature high error popped up in the middle of a big color job. Now it shows 6803 as soon as I power it on.

Technician

Got it, thanks. Support Code 6803 is Canon’s way of saying “internal temperature is high” or the temperature reading is out of range.
Typical causes on PIXMA / MAXIFY / MegaTank models:
• Long continuous printing or photo runs in a hot room → print head overheating.
• Blocked rear/side vents or the printer inside a cabinet → heat can’t escape.
• Residual heat after a paper jam near the fuser/transport area (on some models).
• A temperature sensor glitch, power surge, or low-quality extension cord.
We’ll do a safe cool-down reset, check ventilation, clear obstructions, and see if 6803 is genuine overheating or just a sensor/power issue.

Customer

It’s on a shelf with about 2–3 cm clearance at the back. I’ve been printing a lot. What’s the proper way to cool it and reset 6803?

Technician

Step 1 — Full power drain & cool-down (don’t skip)
1) With the printer already powered off, unplug the power cable from the wall and from the printer.
2) Leave it unplugged for at least 15–20 minutes to let the internal power unit and print head cool. Do not cover it or run a fan directly inside — just let air flow normally.
3) While it cools, move the printer so there’s at least 10–15 cm space at the back and sides. This prevents future “internal temperature high” warnings.
4) Plug the cable directly into a wall outlet (avoid cheap surge strips/extension cords that can cause voltage drop and Canon 6803 style errors).
After the break, power it back on. Tell me if Support Code 6803 appears instantly or only when you start printing again.

Customer

After 20 minutes and moving it out, it starts normally. But when I launch another big print job, 6803 comes back. No other errors.

Technician

Good, that means the printer can boot, but under load it still sees high internal temperature.
Step 2 — Check for blockages & heavy duty cycle
• Open the rear tray, front cover, and paper path panels. Remove any tiny paper scraps or labels near the print head carriage and transport path — jams can trap heat.
• Gently vacuum or blow out dust and lint around the vents (outside only). Do not spray liquid cleaners inside.
• Avoid running hundreds of pages without pause. For many Canon PIXMA/MegaTank models, use short batches: 20–30 pages, brief break, then continue. This alone prevents recurring Support Code 6803.
Try another smaller print (3–5 pages). If 6803 only appears on very long runs, we’re likely dealing with real overheating instead of a pure sensor fault.

Customer

Short jobs are fine. 6803 only happens after a lot of full-color pages. Is this dangerous for the print head or power unit?

Technician

Great question. The 6803 code itself is a protective shutdown: it stops printing before the thermal inkjet head or internal electronics are damaged.
To stay safe:
• Keep the printer in a cool, ventilated room (roughly 10–32 °C / 50–90 °F).
• Use genuine or high-quality ink; clogged nozzles and dry firing increase heat at the head.
• Avoid covering the printer or stacking gear on top that blocks cooling vents.
If 6803 appears quickly, with light use, or you smell heat/see discoloration, stop using it. That can indicate a failing temperature sensor, PSU, or main board. At that point, it’s safer to have a technician (like us via chat or local Canon service) evaluate it instead of repeatedly clearing the error.

Customer

Sometimes 6803 appears right after power on, even when it’s cool. Is there a way to rule out a sensor glitch before I replace the printer?

Technician

Step 3 — Rule out power & firmware quirks
1) Confirm the power cable is the original Canon cable, firmly seated, plugged directly into a grounded outlet.
2) If your model supports it, run a nozzle check and internal test page immediately after boot (before any large job). If 6803 trips during these light tasks, that suggests a sensor or board issue.
3) Check Canon’s site for your exact model and update to the latest firmware if available; some thermal/temperature issues are mitigated by firmware logic.
4) Avoid unofficial “service mode hacks” or disabling protections you might see in random videos — bypassing thermal protection can permanently damage the print head.
If you’d like, I can walk you live through model-specific diagnostics in chat and help decide whether the unit is still safe to use.

Customer

If I follow all this and 6803 still comes back, what’s the next realistic step? Repair, new print head, or straight replacement?

Technician

Good you’re thinking about that now, not after it fails completely.
As a rule of thumb for Support Code 6803:
• If the printer only errors under extreme workloads → spread out jobs, improve cooling, keep using it.
• If 6803 triggers at startup, or with light printing, even after proper cool-down → likely temperature sensor, logic board, or PSU issue.
• On many consumer PIXMA/MegaTank models, a main board or head replacement can approach the cost of a new device.
In our live chat we check exact model, page count, warranty, regional Canon service pricing, and tell you in minutes whether repair is worth it or if replacing the printer is the smarter move financially.

Customer

Understood. For now I just need it running safely without damaging the print head. Anything else to lock in so 6803 doesn’t show again?

Technician

Final checklist to prevent Canon 6803 internal temperature high from coming back:
• Keep 10–15 cm clearance on all sides; never enclose the printer in a tight cabinet.
• Use shorter print batches for dense color jobs; allow 5–10 minute breaks between heavy runs.
• Regularly clean dust from external vents; clear all bits of paper from the paper path.
• Use recommended inks to avoid overworking the thermal elements in the print head.
• If 6803 returns quickly after a proper cool-down, stop forcing resets — that’s the time to consult an expert.
Need help testing or reading your model’s service info? Open the chat and I’ll guide you step by step so you don’t risk permanent damage.

Customer

Thanks, that makes sense. I’ll adjust the placement, break up jobs, and if 6803 shows again I’ll jump into chat.

Technician

Summary: Canon Support Code 6803 means the printer detects an internal temperature risk. Power it down properly, unplug, let it cool, improve ventilation, clear jams and dust, limit heavy continuous runs, and check firmware and power. If the 6803 error persists even after a full cool-down, treat it as a hardware/sensor issue and get tailored help. Want a safe, model-specific plan? Chat with an expert now.

Quick answer: accepted safe fix for Support Code 6803

Recommended fix when your Canon printer shows Support Code 6803 “internal temperature is high”: power off normally, unplug completely, let the printer cool in a well-ventilated spot, remove dust and paper scraps, avoid enclosed cabinets, run shorter batches, and plug directly into a stable outlet. If 6803 returns immediately or with light use, stop forcing prints and consult support or a Whizz Tech expert for a hardware assessment.

FAQ

Step-by-step checklist (most Canon PIXMA/MAXIFY/MegaTank models)

1. Power off with the button, unplug from both printer and wall.
2. Let the device cool in an open space for 15–20 minutes.
3. Check and clear paper scraps and dust from accessible paths (no disassembly).
4. Ensure 10–15 cm clearance around vents; avoid enclosed cabinets.
5. Plug directly into a stable wall outlet; avoid weak extension cords.
6. Print a nozzle check and a few test pages; then small batches.
7. If Support Code 6803 returns quickly, stop and consult an expert or Canon support.

Note for mixed environments (Windows, macOS, mobile)

1. The 6803 warning is generated by the printer hardware, not by Windows or macOS drivers.
2. If 6803 appears regardless of whether you print from PC, Mac, or phone, focus on cooling, vents, and hardware checks rather than driver reinstall.

Sources

• Canon USA — Support Code 6800: Printer problem & power reset guidance
• Canon IJ Manuals — Error code and warning explanations for PIXMA/MegaTank series
• Ahorraentinta — Canon PIXMA error codes overview

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