Brother 'Unable to Print 4F' and 'Unable to Init 4F': ink system fault

What causes it

• Air drawn into the ink lines after a cartridge ran completely empty
• The purge pump seized with dried ink after weeks or months of disuse
• The maintenance assembly saturated so it cannot move ink away
• A cartridge with a damaged seal letting air into the supply
• Pump or maintenance unit mechanical failure

How to fix it, in order

Work down the list and stop when the printer recovers. The steps are ordered from most likely and least invasive to last resort.

1. Power down and rest the machine

   Hold the power button until the display clears and unplug at the wall for at least ten minutes. Brother inkjets latch this fault, and a full power-down is what allows the machine to attempt a fresh priming cycle rather than resuming a failed one. Listen carefully to what it does on the next boot.

2. Check every cartridge is full and genuine

   Open the ink cartridge cover and take each cartridge out. Replace anything that is empty or low with a full genuine Brother LC cartridge, and remove the orange protective cap from each new one before fitting. Push each in until the lever snaps shut. A machine trying to prime against an empty cartridge cannot pass this check.

3. Look for the orange transport part

   If the machine has recently been moved or is new, check the ink cartridge compartment for the orange protective piece Brother fits for shipping. Printing with it installed blocks the ink path completely. Remove it and store it somewhere safe for future transport.

4. Soak the capping station overnight

   With the machine unplugged, raise the scanner cover and move the carriage to the middle by hand. On the right-hand side you will see the rubber cap and wiper the head parks against. Put a few millilitres of warm distilled water into the cap with a syringe, slide the carriage back over it, and leave the machine overnight to soften dried ink in the pump path.

5. Run a single purge after the soak

   Reconnect power and switch on. If the machine boots, go to Menu, then Ink, then Cleaning, and run one cycle for the affected colour group. Print a Print Quality Check page afterwards. One or two cycles is the limit; repeated purging fills the ink absorber and moves you towards the separate absorber-full error.

6. Check for the absorber warning

   If the display has previously mentioned the ink absorber being near full, that condition interacts with this one, because a saturated absorber cannot accept more purge ink. Note whether that warning has appeared, since it changes the repair decision entirely.

7. Listen to the pump on the next boot

   Power on and listen at the right-hand side during initialisation. A healthy machine makes a short whirring and squelching noise. Silence, or a repeated clicking, means the pump drive is not turning, and that is a mechanical failure rather than dried ink.

Printers that show this code

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