Mitsubishi Electric City Multi Aircon 5104 Error Code
Capture the Mitsubishi Electric City Multi 5104 fault correctly, then see what should be checked before parts are quoted. Confirm whether the indoor or outdoor unit reported the code; the meaning differs between the indoor and outdoor unit.
What does Mitsubishi Electric 5104 mean?
Mitsubishi Electric City Multi 5104 is listed as indoor-unit outside-temperature sensor TH24 fault and outdoor-unit discharge temperature sensor TH4 fault in VRF rows such as City Multi VRF indoor-unit diagnostics, City Multi VRF outdoor-unit diagnostics. This meaning comes from the manufacturer's own diagnostic material. Check whether the indoor or outdoor unit shows the code before parts are quoted; the meaning depends on it. Confirm whether the indoor or outdoor unit reported the code before accepting a parts quote.
What to do now
Use these steps before customer action, a sensor check, or PCB quote.
Treat it as a fault signal
If 5104 remains displayed or cooling is still abnormal, preserve the code and arrange diagnosis.
No manufacturer reset steps listed for 5104
Capture the complete 5104 display and model stickers first. The manufacturer lists no customer reset procedure; do not treat a generic power-cycle as manufacturer guidance.
Send these to us
5104 error code, a clear display photo, Mitsubishi Electric City Multi model stickers, affected rooms, operating state when the code appeared, and when the fault appears
Choose the listing that matches your unit
The same code has more than one listed meaning. Match the model family, the system type and the unit that shows the code before approving parts.
| Code | What it means | What to check first |
|---|---|---|
| 5104 - indoor unit | Indoor-unit outside-temperature sensor TH24 fault | Match this meaning to your installed model and the unit that shows the code, then use the checks below. |
| 5104 - outdoor unit | Outdoor-unit discharge temperature sensor TH4 fault | Match this meaning to your installed model and the unit that shows the code, then use the checks below. |
- Code
- 5104 - indoor unit
- What it means
- Indoor-unit outside-temperature sensor TH24 fault
- What to check first
- Match this meaning to your installed model and the unit that shows the code, then use the checks below.
- Code
- 5104 - outdoor unit
- What it means
- Outdoor-unit discharge temperature sensor TH4 fault
- What to check first
- Match this meaning to your installed model and the unit that shows the code, then use the checks below.
Guidance for your model
Notes that match the code to your exact model. Electrical, refrigerant, wiring, resistance and component checks are for a technician.
| Detail | What it says |
|---|---|
| Diagnostic note | Check TH24 resistance, connector contact, and the indoor control board if the sensor and wiring test normally. |
| Diagnostic note | Check TH4 resistance, lead-wire condition, connector contact, and the control-board monitor reading against actual temperature. |
| Singapore / model note | Official Mitsubishi Electric Singapore City Multi PDF page 4, primary fault-code table for the indoor unit. Confirm the installed City Multi equipment and the unit reporting the code before parts replacement. The table also shows preliminary code 1202 in parentheses; it is diagnostic context, not a separate public fault route. |
| Singapore / model note | Official Mitsubishi Electric Singapore City Multi PDF page 5, primary fault-code table for the outdoor unit. Confirm the installed City Multi equipment and the unit reporting the code before parts replacement. The table also shows preliminary code 1202 in parentheses; it is diagnostic context, not a separate public fault route. |
- Detail
- Diagnostic note
- What it says
- Check TH24 resistance, connector contact, and the indoor control board if the sensor and wiring test normally.
- Detail
- Diagnostic note
- What it says
- Check TH4 resistance, lead-wire condition, connector contact, and the control-board monitor reading against actual temperature.
- Detail
- Singapore / model note
- What it says
- Official Mitsubishi Electric Singapore City Multi PDF page 4, primary fault-code table for the indoor unit. Confirm the installed City Multi equipment and the unit reporting the code before parts replacement. The table also shows preliminary code 1202 in parentheses; it is diagnostic context, not a separate public fault route.
- Detail
- Singapore / model note
- What it says
- Official Mitsubishi Electric Singapore City Multi PDF page 5, primary fault-code table for the outdoor unit. Confirm the installed City Multi equipment and the unit reporting the code before parts replacement. The table also shows preliminary code 1202 in parentheses; it is diagnostic context, not a separate public fault route.
What to check before repair
Use this split to separate safe evidence capture from the tests a technician should prove before quoting parts.
| You can check | Technician should confirm |
|---|---|
| Before taking any system action on 5104, take a clear display photo. | Confirm which sensor 5104 maps to on the exact model table. |
| Capture the Mitsubishi Electric City Multi indoor and outdoor model stickers so the correct family row is used. | Measure the sensor value against the service-manual resistance or voltage range. |
| The manufacturer lists no customer reset procedure for this code. Note whether one room, several rooms, or the whole system is affected. | Check connector condition, harness continuity, and PCB input before replacing boards. |
- You can check
- Before taking any system action on 5104, take a clear display photo.
- Technician should confirm
- Confirm which sensor 5104 maps to on the exact model table.
- You can check
- Capture the Mitsubishi Electric City Multi indoor and outdoor model stickers so the correct family row is used.
- Technician should confirm
- Measure the sensor value against the service-manual resistance or voltage range.
- You can check
- The manufacturer lists no customer reset procedure for this code. Note whether one room, several rooms, or the whole system is affected.
- Technician should confirm
- Check connector condition, harness continuity, and PCB input before replacing boards.
Sensor or PCB decision
Mitsubishi Electric City Multi 5104 is usually repair-first if a sensor or harness reading is confirmed. Board replacement should wait until the sensor circuit is tested.
Sensor replacement is usually targeted when resistance or voltage readings are out of range.
Harness or connector damage can look like a sensor fault until continuity is checked.
PCB replacement is a later step if the sensor and wiring test correctly.
Mitsubishi Electric 5104 questions
What does the Mitsubishi Electric 5104 error mean?
Can I fix a Mitsubishi Electric 5104 error myself?
Is it safe to keep running the aircon with a 5104 error?
What causes a Mitsubishi Electric 5104 error?
Will a Mitsubishi Electric 5104 error need a repair or a full replacement?
What should I send a technician about a Mitsubishi Electric 5104 error?
Where to go next
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