Fujitsu Error Code E2:00: Room Temp Sensor Open Circuit
How to Fix Fujitsu Code E2:00
- Step 1: Power cycle the unit by turning off the breaker that supplies power to the indoor unit for 5 minutes, then turn it back on. This may reset the system and clear a temporary error.
- Step 2: Visually inspect the area around the indoor unit for any obvious signs of damage, such as chewed wires or loose connections. Do not open the unit.
- Step 3: If the error persists after power cycling and you see no obvious damage, contact a qualified HVAC technician to diagnose and repair the issue.
How to Reset Fujitsu Code E2:00
- 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 E2:00 Mean?
The Fujitsu error code E2:00 indicates that the indoor unit's main control board isn't receiving a signal from the room temperature sensor. This sensor, also called a thermistor, is responsible for telling the system the current room temperature. Without this information, the unit can't properly regulate heating or cooling, and the system will lock out to prevent potential issues like the unit running constantly or not at all. This error is specific to the indoor unit and will prevent it from operating until the issue is resolved. It's important to address this promptly to restore comfortable temperatures and efficient operation.
Common Causes
- Faulty room temperature sensor (thermistor)
- Loose or damaged wiring between the sensor and the main control board
- Corrosion on the sensor or control board connections
- Defective main control board in the indoor unit
- Rodent damage to the sensor wiring
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| Unit displays E2:00 error | Measure resistance across the room temperature sensor terminals at the main control board | Resistance should match the thermistor's temperature/resistance chart (typically around 10k ohms at 25°C). |
| Resistance is outside the expected range | Disconnect the sensor and measure resistance directly at the sensor terminals | Same resistance as measured at the board. If different, wiring is the issue. |
| Sensor resistance is correct | Check voltage at the sensor input on the main control board | Typically 5V DC |
| Voltage is absent or unstable | Inspect the main control board for signs of damage (burn marks, corrosion) | Board should appear clean and undamaged. |
Applicable Fujitsu Models
Replacement Parts
| Part | OEM Number | Est. Cost | Where to Buy |
|---|---|---|---|
| Room Temperature Sensor (Thermistor) | 9704378071 | — | Find Part |
| Main Control Board | — | — | — |
Related Codes on Same Models
Other codes that affect the same Fujitsu model families as E2:00.
| Code | Description | Severity |
|---|---|---|
| E0:00 | Communication Error (Indoor to Remote) | Warning |
| E1:00 | Communication Error (Indoor to Outdoor) | 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 |
| EE:00 | Communication Error (Multi-System) | Warning |