What does Mitsubishi Electric 31 / LED1 7x, LED2 lit mean?
Mitsubishi Electric 31 / LED1 7x, LED2 lit is listed as high-low pressure bypass valve or cooling evaporating temperature drop prevention control in Multi-Split rows such as FP Series, Starmex R32. This meaning comes from the manufacturer's own diagnostic material. Confirm the exact model, series, or signal row before accepting a parts quote.
Low refrigerant, active leak, restriction, or abnormal pressure reading.
Dirty condenser, weak outdoor fan, blocked airflow, or high-load operation.
Pressure sensor, expansion path, or compressor protection after readings are taken.
What to do now
Use these steps before customer action, gas work, a pressure check, or parts quote.
Treat it as a fault signal
Stop using the unit if 31 / LED1 7x, LED2 lit returns with weak cooling, frost, hissing, or outdoor-unit tripping.
No manufacturer reset steps listed for 31 / LED1 7x, LED2 lit
Capture the complete 31 / LED1 7x, LED2 lit pattern 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
31 / LED1 7x, LED2 lit blinking light, a short video of the blinking-light sequence, Mitsubishi Electric model stickers, affected rooms, operating state when the code appeared, and cooling-loss timeline and any recent gas top-up
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 | Do not keep resetting the system if this pattern returns. Record the model number, lamp or LED pattern, and affected rooms before booking diagnosis. |
| Singapore / model note | Official Mitsubishi Electric checklist action: Check filters, refrigerant amount, and indoor or outdoor air short-cycling. |
- Detail
- Diagnostic note
- What it says
- Do not keep resetting the system if this pattern returns. Record the model number, lamp or LED pattern, and affected rooms before booking diagnosis.
- Detail
- Singapore / model note
- What it says
- Official Mitsubishi Electric checklist action: Check filters, refrigerant amount, and indoor or outdoor air short-cycling.
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 31 / LED1 7x, LED2 lit, take a short video of the blinking-light sequence. | Match 31 / LED1 7x, LED2 lit to low-pressure, high-pressure, leak, or refrigerant-cycle protection. |
| Capture the Mitsubishi Electric indoor and outdoor model stickers so the correct family row is used. | Measure operating pressures, coil temperatures, airflow, and outdoor fan condition. |
| The manufacturer lists no customer reset procedure for this code. Note whether one room, several rooms, or the whole system is affected. | Leak-check or pressure-test before recommending another refrigerant top-up. |
- You can check
- Before taking any system action on 31 / LED1 7x, LED2 lit, take a short video of the blinking-light sequence.
- Technician should confirm
- Match 31 / LED1 7x, LED2 lit to low-pressure, high-pressure, leak, or refrigerant-cycle protection.
- You can check
- Capture the Mitsubishi Electric indoor and outdoor model stickers so the correct family row is used.
- Technician should confirm
- Measure operating pressures, coil temperatures, airflow, and outdoor fan condition.
- 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
- Leak-check or pressure-test before recommending another refrigerant top-up.
What changes the next step
These clues decide whether the first check is room-side, shared outdoor-side, refrigerant-side, listed-meaning, or model-family confirmation.
| What you see | What it points to |
|---|---|
| Only one indoor unit shows 31 / LED1 7x, LED2 lit. | The affected room, indoor board path, wiring route, or local component should be checked first. |
| Several rooms or the outdoor unit show the same 31 / LED1 7x, LED2 lit fault. | Prioritise the shared outdoor side, pressure conditions, airflow, and refrigerant circuit. |
| Cooling is weak, frost appears, or the outdoor unit trips under load. | Pressure, airflow, leak, and condenser checks should come before another top-up. |
| The model family is different from the row you found online. | Use the model or series filter first; same-looking codes can still belong to different diagnostic tables. |
| The model belongs to Multi-Split rows such as FP Series, Starmex R32. | This meaning comes from the manufacturer's own diagnostic material. Match the code to your model's listing before parts are quoted. |
- What you see
- Only one indoor unit shows 31 / LED1 7x, LED2 lit.
- What it points to
- The affected room, indoor board path, wiring route, or local component should be checked first.
- What you see
- Several rooms or the outdoor unit show the same 31 / LED1 7x, LED2 lit fault.
- What it points to
- Prioritise the shared outdoor side, pressure conditions, airflow, and refrigerant circuit.
- What you see
- Cooling is weak, frost appears, or the outdoor unit trips under load.
- What it points to
- Pressure, airflow, leak, and condenser checks should come before another top-up.
- What you see
- The model family is different from the row you found online.
- What it points to
- Use the model or series filter first; same-looking codes can still belong to different diagnostic tables.
- What you see
- The model belongs to Multi-Split rows such as FP Series, Starmex R32.
- What it points to
- This meaning comes from the manufacturer's own diagnostic material. Match the code to your model's listing before parts are quoted.
Pressure, leak, or airflow decision
Mitsubishi Electric 31 / LED1 7x, LED2 lit needs measured pressure, airflow, and leak evidence before gas work is approved. Replacement only becomes serious when the leak, compressor, or coil repair is uneconomical.
A top-up alone is poor value if the leak source is not found.
High-pressure faults often come from airflow, condenser, fan, or overcharge conditions.
Coil leaks or compressor-related findings can shift older systems toward replacement.
Mitsubishi Electric 31 / LED1 7x, LED2 lit questions
What does the Mitsubishi Electric 31 / LED1 7x, LED2 lit error mean?
Can I fix a Mitsubishi Electric 31 / LED1 7x, LED2 lit error myself?
Is it safe to keep running the aircon with a 31 / LED1 7x, LED2 lit error?
What causes a Mitsubishi Electric 31 / LED1 7x, LED2 lit error?
Will a Mitsubishi Electric 31 / LED1 7x, LED2 lit error need a repair or a full replacement?
What should I send a technician about a Mitsubishi Electric 31 / LED1 7x, LED2 lit error?
Where to go next
Confirm the fault
Share the error code, model number and symptoms so we can assess the likely cause.
Not the right code?
Browse the full Mitsubishi Electric list or check a few codes in the same fault category.
Read next
Use these if the quote mentions the parts, checks, or repair path this code points to.