Fujitsu AC Error Code 04 — Indoor Fan Motor Fault

What Does This Error Mean?

Error 04 on a Fujitsu AC means the indoor fan motor is locked — the control board commanded the fan to run but detected no movement. Without the indoor fan, the evaporator coil would freeze over, so the AC shuts down immediately. Causes range from a jammed fan wheel to a failed motor bearing or winding.

Affected Models

Fujitsu ASTG Series
Fujitsu ASYG Series
Fujitsu AOTG Series
Fujitsu Inverter Split AC (all models)
Fujitsu General Split AC

Common Causes

Foreign object (insect, leaf, debris) jammed in the fan wheel
Fan motor bearing seized — motor cannot turn
Fan wheel cracked and rubbing against the housing
Fan motor winding failure — motor draws too much current and trips protection
PCB not supplying correct voltage to the fan motor
Hall effect sensor in the motor failed — board cannot confirm fan is spinning

How to Fix It

Switch off the AC and circuit breaker.

Do not attempt to restart repeatedly — the motor protection is preventing further damage.
Open the front panel of the indoor unit and visually inspect the fan wheel.

With the power OFF, use a torch to look at the fan wheel through the grille. If you can see a foreign object stuck in the blades, carefully remove it with long-nose pliers or tweezers.
Try rotating the fan wheel manually (power OFF).

Reach in carefully and attempt to rotate the fan wheel by hand. It should spin freely with light resistance. If it is completely stuck or grinds, the bearing or motor has seized and needs professional replacement.
If the fan spins freely after removing an obstruction, restore power and restart.

If Error 04 clears and the fan runs normally, the obstruction was the cause.
If the fan is seized or Error 04 returns, book a technician.

A Fujitsu fan motor replacement typically costs less than a PCB replacement and is a reliable repair.

When to Call a Professional

Error 04 requires a licensed technician unless you can see and remove an obvious obstruction. Fan motor replacement involves disassembling the indoor unit and working with electrical components.

Frequently Asked Questions

Can insects cause Fujitsu Error 04?

Yes — it is not uncommon for geckos, cockroaches, or other insects to find their way into the indoor unit and jam the fan wheel. Regular servicing (at least once a year) and mesh on the indoor unit drain outlets can reduce the risk.

How long does a Fujitsu indoor fan motor last?

In normal use, Fujitsu indoor fan motors typically last 8–15 years. Failure is more likely in units that are rarely serviced, run continuously for many hours per day, or are installed in dusty or humid environments.