Fujitsu Error Code EE:00: Communication Error (Multi-System)
How to Fix Fujitsu Code EE:00
- Step 1: Power cycle the entire system by turning off the breaker that supplies power to the outdoor unit for 5 minutes, then turn it back on. This can sometimes reset the communication.
- Step 2: Check the physical connections of the communication wires at the indoor unit. Ensure the wires are securely connected to the terminals. Do not open the unit, just inspect the visible wiring.
- Step 3: If the error persists after power cycling, contact a qualified HVAC technician experienced with Fujitsu mini-split systems for diagnosis and repair.
How to Reset Fujitsu Code EE:00
- Turn off the unit using the remote control or wall controller.
- Turn off the circuit breaker for the outdoor and indoor units. Wait 60 seconds.
- Restore power at the breaker.
- Turn the unit on with the remote control. If the error returns, the fault needs professional diagnosis.
Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.
What Does Fujitsu Error Code EE:00 Mean?
The EE:00 error code on your Fujitsu multi-zone mini-split system indicates a communication problem. Specifically, the indoor unit(s) can't talk to the outdoor unit. Think of it like a broken telephone line – the units can't exchange information needed to operate correctly. This communication breakdown prevents the system from knowing what the indoor temperature is, what mode it should be in (heating, cooling, etc.), or even whether it should be running at all. This typically results in a complete system lockout, meaning no heating or cooling until the issue is resolved. Because mini-splits rely on constant communication to modulate their output and maintain efficiency, this error is significant and needs attention.
Common Causes
- Wiring issues between the indoor and outdoor units (loose connections, damaged wires).
- A faulty outdoor unit control board.
- A defective indoor unit control board.
- Electrical noise or interference on the communication line.
- Incorrect system configuration or addressing (especially after unit replacement).
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| System displays EE:00 error | Measure voltage between communication terminals on the outdoor unit control board | Typically 24-36VDC, but refer to Fujitsu's service manual for the specific voltage range for your model. |
| Communication voltage is outside the specified range | Inspect the communication wiring for shorts, opens, or damage. | Wiring should be intact with good insulation and properly terminated. |
| Wiring is good, but communication voltage is still incorrect | Check the outdoor unit control board for signs of damage (burn marks, corrosion). | Control board should appear physically sound with no visible damage. |
| Communication voltage is correct at the outdoor unit | Measure the communication voltage at the indoor unit. | Should be approximately the same voltage as measured at the outdoor unit. |
Applicable Fujitsu Models
Replacement Parts
| Part | OEM Number | Est. Cost | Where to Buy |
|---|---|---|---|
| Outdoor Unit Control Board | — | — | — |
| Indoor Unit Control Board | — | — | — |
| Communication Wire | — | — | — |
Related Codes on Same Models
Other codes that affect the same Fujitsu model families as EE:00.
| Code | Description | Severity |
|---|---|---|
| E0:00 | Communication Error (Indoor to Remote) | Warning |
| E1:00 | Communication Error (Indoor to Outdoor) | Warning |
| E2:00 | Room Temp Sensor Open Circuit | Warning |
| E3:00 | Room Temp Sensor Short Circuit | Warning |
| E4:00 | Indoor Coil Sensor Open | Warning |
| E5:00 | Indoor Coil Sensor Short | Warning |
| E6:00 | Outdoor Coil Sensor Fault | Warning |
| E7:00 | Outdoor Ambient Sensor Fault | Warning |
| E8:00 | Indoor Fan Motor Fault | Warning |
| E9:00 | Drain Pump / Float Switch | Warning |