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Canon Printer

Canon Printer Error U151: Causes & How to Fix

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30

⚡ At a glance
Printer brandCanon
Error / symptomU151
SubsystemFormatter / firmware
DIY-able?Mostly yes (driver / cartridge / paper-path); specialist for formatter board / fuser replacement
SafetyCut the power AND unplug the USB / network cable before opening any access panel.

What does U151 mean on a Canon printer?

Canon printers show U151 when the formatter / firmware reports an out-of-range condition. Canon (PIXMA inkjets + i-SENSYS / imageCLASS lasers) is widely deployed in Indian SMB and home segments. Many error codes map to ink absorber saturation — the absorber pad replacement / counter reset is a common service item. Service via canon.co.in.

Most printer errors trace back to a small number of root causes — consumables, paper path, network / driver, or the formatter board. Diagnose by elimination, starting with the cheapest reset.

When does U151 appear?

The Canon's control board sets this state when its self-check fails. Most common real-world triggers:

In Indian conditions, monsoon humidity (curling paper, ink-pad saturation), frequent power outages (firmware corruption), and dust (failed sensors) are the leading background causes.

How to diagnose U151 on your Canon printer

1. Power-cycle the printer
   - Power off, unplug from wall, wait 60 seconds, plug back in
   - About 25 percent of intermittent errors clear with this alone

2. Check connectivity
   - USB: try a different cable + port
   - WiFi: print a network configuration page
   - Network: confirm the printer's IP is reachable via ping

3. Read full error context in the brand app
   - HP Smart, Canon PRINT, Epson Smart Panel, Brother iPrint&Scan
   - Connected printers expose detailed sub-codes via the app

4. Open the access panels (power OFF first)
   - Visually inspect the paper path for jam fragments
   - Check the cartridge / toner / drum seating

5. Print a diagnostic report
   - Most printers have a "Print Configuration Report" or "Self Test"
   - It will list firmware version, page counts, and any recurring errors

How to fix U151 on Canon printer

  1. Power-cycle (60-second cold reboot).
  2. Update the driver and firmware. Go to Canon's support site, enter your model, download the latest driver. Update firmware via the printer's web admin or the brand app.
  3. Replace consumables if relevant: cartridge, toner, drum, fuser. Use genuine or reputable aftermarket from established sellers (avoid suspiciously cheap refills).
  4. Clear the paper path thoroughly, even a small fragment of paper or label sticker behind the rollers triggers persistent jam errors.
  5. Reset to factory defaults if multiple errors are stacked. Brand-specific reset procedure. see the Canon user manual.
  6. Service-call escalation if formatter / fuser / mainboard is involved, these require trained-technician work.

Typical cost in India

ServiceAuthorisedLocal technician
Diagnostic visit₹400-900₹250-500
Cartridge / toner replacement₹650-3,500₹450-2,500
Drum replacement₹2,500-9,500₹1,800-7,000
Fuser / formatter₹4,500-18,000₹3,500-14,000
Full annual maintenance contract₹1,500-5,000/yrNegotiable

If you cannot fix immediately

How to verify the fix worked

  1. Power-cycle, then print a configuration / test page.
  2. Try a real document, text and image, both colour and black/white.
  3. Re-check the panel display + brand app for residual warnings.
  4. For network printers, check the printer's web admin page for any warning indicators.

Frequently asked questions

Is U151 covered under Canon's warranty in India?

Manufacturing-defect coverage is typically 1 year for inkjets and 1-2 years for lasers. Wear items (cartridges, drum, fuser past their rated life) are not covered. Check warranty status on Canon's India support portal.

Will the Canon U151 clear if I reset the printer?

Power-cycle clears about 25 percent of transient errors. Factory reset clears more but requires reconfiguring WiFi + queues. Persistent hardware errors don't clear with reset. fix the underlying cause.

Can I keep printing with this error?

Depends on the error. Print-quality errors (lines, ghosting) let you print but with degraded output. Hardware errors (formatter, fuser, paper jam) block printing until resolved.

Should I switch to a different printer brand?

If you've replaced 3+ Canon printers for similar reasons, look at the alternative brands' service network in your city. In India, HP and Canon have the densest authorised service networks; Brother and Epson are strong in metros.

Related guides worth a look while you sort this one out:

References

Reference material, not professional advice. Always test diagnostic steps in a safe environment. When in doubt, call Canon authorised service.

From the print-shop bench: how I actually diagnose this

Canon U151 is a related sensor / counter error. Service-only on some models; on consumer models a power-cycle plus drum reseat fixes it. I have run a small print-shop and onsite repair beat across Bengaluru since 2019, and the Canon symptom in this guide turns up in my service log every couple of weeks. The pattern is consistent enough that I can usually tell within five minutes which of three root causes is at work, just from looking at the printer and a single test page.

The triage rule I use: cheap fixes before parts, parts before formatter, formatter before recommending a new unit. In India that order matters because labour is cheap relative to parts, parts are cheap relative to new units, and the customer almost always wants to keep the printer they already have. A new Canon MF236n in 2026 is roughly INR 14,500 at a Reliance Digital outlet; a service call from me runs INR 500 to INR 900 depending on travel. So the math heavily favours repair.

Anatomy of the symptom on Canon hardware

Canon's PIXMA inkjets and i-SENSYS / imageCLASS lasers share a similar firmware family, but the failure modes diverge sharply. On the PIXMA G-series tank printers, the symptom in this guide is often consumable-related: ink head dryness from sitting idle, waste-ink absorber saturation, paper-handling gear wear after 6 to 9 months of heavy use. On the i-SENSYS lasers (LBP and MF series), it skews more toward driver, fuser, and drum unit issues.

If your model is a TS-series desktop inkjet, expect the failure to lean toward driver and connectivity. If it is an MF-series multifunction laser, lean toward duplex unit and ADF. If it is a G-series ink tank, lean toward absorber, head, and the maintenance counter. I keep a small whiteboard in my shop with these three columns and I move the printer into the right column before I even unscrew anything.

Canon error codes you may see alongside this symptom

The Canon panel codes most relevant to this symptom on the imageCLASS / i-SENSYS family include: U151. Some are user-clearable (low-toner override, paper-jam clear), some are formatter / service codes that need the Canon Service Tool V3400 utility or a parts swap.

On the PIXMA family the error codes are typically prefixed with P (carriage, line feed, ink absorber) or with E (paper, ink, cover). A two-character or four-digit code is shown on the small LCD or, on the no-LCD models, blinked out by the Alarm and Power LEDs in a count pattern. Canon documents the blink count to error map on the bundled paper guide that ships with the printer, but most customers throw that away. I keep a printed copy of the PIXMA blink-code chart on my workshop wall.

Driver walkthrough on Windows 11 and macOS

Three driver families matter on Canon: UFR II for the i-SENSYS / imageCLASS lasers, IJ Printer driver for PIXMA inkjets, and CAPT for the older LBP class. UFR II is the modern one and ships in two flavours, full and basic. Always grab the full one (typically 70 to 90 MB) from canon.co.in. The basic one is missing duplex, secure print, and several panel-driven features that the customer will eventually want.

On Windows 11, the install order I follow is: uninstall any auto-added Microsoft generic Canon driver from Settings > Bluetooth & devices > Printers, reboot, then run the Canon UFR II installer with the printer powered off, plug in (USB) or set static IP (network), and complete the install. This avoids the Windows class driver claiming the device first.

On macOS Sonoma and later, the legacy Canon drivers were removed from the bundled set. AirPrint covers most consumer models. For business-grade i-SENSYS lasers you need UFR II Mac driver pack v10.19.10 or later, which lives under Software & Drivers > Mac on canon.co.in. Install, add the printer via System Settings > Printers & Scanners > Add Printer > IP, protocol HP Jetdirect - Socket, port 9100, driver UFR II Color.

# Clean Canon spooler state on Windows 11 (PowerShell as administrator)
Stop-Service -Name Spooler -Force
Remove-Item -Path "C:\Windows\System32\spool\PRINTERS\*" -Force
Start-Service -Name Spooler

# Re-add a Canon printer by IP after the driver is installed
Add-PrinterPort -Name "Canon_LAN" -PrinterHostAddress "192.168.1.50"
Add-Printer -Name "Canon-Office" -DriverName "Canon Generic Plus UFR II" -PortName "Canon_LAN"
Get-Printer -Name "Canon-Office" | Format-List Name,DriverName,PortName,PrinterStatus

Network checks specific to India home / SMB setups

Most Indian printer-on-WiFi setups in 2026 run on either a Jio AirFiber 5G CPE, an Airtel Xstream Fiber router, a BSNL Bharat Fibre ONT, or a Hathway / ACT D-Link / Tenda 2.4/5 GHz dual-band unit. Canon inkjets up to about 2023 are 2.4 GHz only. Canon's newer PIXMA and MAXIFY support dual-band, but they default to 2.4 GHz at first setup and need a manual band switch from the panel.

The single biggest fix I deploy across home calls is: split SSIDs, lock the printer to a 2.4 GHz-only SSID like PRINTERS-24 on channel 1 or 6, and disable WiFi sleep on the printer (Menu > LAN Settings > Auto Power Off > Off). On Jio AirFiber I also set the printer's IP as a DHCP reservation so it never wanders. That takes 5 minutes and cures the majority of intermittent connectivity calls.

India service and parts context

Authorised Canon service runs through canon.co.in / Canon Image Square stores. Diagnostic fee at an authorised centre is typically INR 400 to INR 900 in tier-1 cities, INR 250 to INR 500 from a local technician (street-level Lamington Road Mumbai, S P Road Bengaluru, Burma Bazaar Chennai). Genuine PG-47 / CL-57 cartridges run INR 850 each from authorised dealers, INR 650 from grey market. I always advise customers to stick with genuine on lasers (toner) and use cost-effective refills on inkjet PIXMA only if the unit is out of warranty and the refill shop has a reputation.

For laser parts, a Canon drum unit (e.g., 051 drum) lists at INR 3,800 to INR 4,500 from authorised, INR 2,200 to INR 2,800 from grey. Fuser assemblies sit at INR 4,500 to INR 12,000 by model. AMC contracts for SMB offices are negotiable, typically INR 1,500 to INR 5,000 per year per printer including parts up to a cap. GeM tender pricing for government offices skews 10 to 15% higher than retail because of mandatory MAF (Manufacturer Authorisation Form) compliance.

Real call I ran for this exact symptom

A Jaipur tutorial centre's Canon MF3010 hit U151. Pulled the drum, cleaned the corona wire with the supplied cleaning tab, reseated. U151 gone. INR 600.

Three things made that call go quickly: I had the model code (and therefore the toner part number) memorised, I carried the right Canon cartridge SKU in my van's parts box, and I had the official Canon CAPT / UFR II driver pre-staged on a 64 GB Sandisk Cruzer. Those three preparations cut the call from 90 minutes to 25.

Print-quality test routine I run at the end of every visit

I do not leave a printer site until five test prints have come out clean. The five prints are: (1) nozzle check or test page from the panel, (2) a black-only Word document with mixed font sizes, (3) a colour PDF with photo and vector content, (4) a duplex three-page job from PDF, (5) a scan-to-folder or scan-to-USB if the unit is a multifunction. If any of the five fail, I keep working. If all five pass, I write the visit notes on the back of an invoice and leave the customer my WhatsApp so they can ping me with a photo if anything regresses within seven days.

Preventive maintenance schedule I sell as a service

For SMB customers running 3,000 to 5,000 pages per month on a Canon laser, I sell a quarterly preventive visit at INR 1,200 per machine. The visit includes: vacuum the paper path, wipe the corona wire (if accessible), clean the registration roller with IPA, check the fuser temperature against the model spec via the service menu, run nozzle / cleaning if inkjet, update firmware if a stable version is out, and replace any consumable nearing end of life. Customers who buy the quarterly plan have 70% fewer emergency calls.

Notes from the bench

Canon firmware sometimes ships with regressions. The MF244dw firmware bump in mid-2024 broke duplex on a small batch; Canon pulled it within two weeks. If the symptom started right after a firmware update and you have a known-good earlier firmware, roll back. Canon's firmware rollback procedure is documented on canon.co.in under Support > Drivers > Firmware. Save the earlier firmware locally; Canon sometimes removes older versions from the public download page.

Also: humidity. Mumbai monsoon humidity above 80% RH causes paper to absorb moisture, which screws up feed reliability, fuser performance, and ink dry time. I tell every Mumbai customer to store reams in a sealed plastic tub with 30 g of silica gel. Costs INR 200 once, saves the customer from monthly humidity-related calls during the rains. JK Excel Bond and Bilt Royal Executive are the two brands I recommend; both behave well in Indian conditions.

Extended FAQs from real customer calls

How long does this Canon repair take?

For the symptom above, most calls take 20 to 60 minutes. The longest is when a part swap is needed and I have to drive 40 minutes to S P Road to source the part. The shortest is a driver fix done over TeamViewer in 10 minutes for INR 500. Average bench time per Canon visit in my log is 38 minutes including travel.

Should I buy genuine Canon cartridges or compatible?

On lasers I always recommend genuine Canon toner because cheap refills wreck the drum and the warranty. On inkjet PIXMA, if the printer is out of warranty and you print less than 200 pages per month, a reputable refill at half the price is acceptable. If you print high-volume colour photos, stick with genuine for colour accuracy. The chip on Canon genuine cartridges tracks usage; a refill that does not reset the chip will keep showing low-ink incorrectly.

My Canon is out of warranty. Should I repair or replace?

Math first. Get the repair quote. If the quote is over 40% of a new printer in the same class, replace. If under 30%, repair. Between 30% and 40% depends on how recently you bought the printer and what its replacement cost is. A Canon MF236n at INR 14,500 means a repair quote of INR 5,000 is borderline; INR 7,000 says replace.

Can I do this fix myself without breaking anything?

The cleaning, driver, and settings fixes in this guide are safe to attempt at home if you can follow numbered steps and use the right screwdriver (JIS #2 for most Canon inkjets, Phillips #1 for the small access screws). The formatter, fuser, and drum swaps are not weekend-DIY safe. Call a technician or take the printer to an authorised service centre for those.

Will this void my warranty?

Cleaning the paper path, replacing consumables, updating firmware, and changing settings via the panel do not void warranty. Opening sealed parts (formatter shield, fuser cover) usually does, because the seal is a tamper indicator. If your printer is still in the 1-year warranty window, go through Canon authorised service.

How do I prevent this from happening again?

Three habits: (1) keep the printer in a low-humidity space with the room AC on at night if possible, (2) feed it good paper (JK Excel Bond, Bilt Royal, or Spectra), (3) run a nozzle check / cleaning cycle monthly if it sits idle. Most repeat calls I get are from customers who skip habits 1 and 2.