Daikin aircon P4 error code
Use this Daikin P4 error code guide to decide when to stop resetting, what to capture, and what to check before parts are quoted. Match the model first; same-looking codes can point to different rows.
What does Daikin P4 mean?
Daikin P4 is listed as faulty inverter circuit heatsink temperature sensor and malfunction of radiation fin temperature sensor in Inverter Split, Multi-Split, Ceiling Cassette rows such as EZi, iSmart ENVi. The loaded row is source-backed by official diagnostic material. Do not collapse this code across model families; use the model, series, or system type to choose the right row. Confirm the exact model, series, or signal row before accepting a parts quote.
Open, shorted, displaced, or out-of-range thermistor or pressure-sensor reading.
Loose sensor connector, damaged sensor harness, or water-affected wiring.
PCB input fault after the sensor and wiring readings are confirmed.
What to do now
Use these steps before another reset, sensor check, or PCB quote.
Treat it as a fault signal
If P4 returns or cooling is still abnormal, stop treating it as a simple reset issue.
Reset P4 once
Capture the P4 display first, then power-cycle once only and note whether the same fault returns.
Send these to us
P4 error code, a clear display photo, Daikin model stickers, affected rooms, reset result, and when the fault appears
Source-specific guidance
These diagnostic-reference notes help match the code to the exact model. Electrical, refrigerant, wiring, resistance, and component checks are technician work, not DIY steps.
| Source detail | What it says |
|---|---|
| Source repair action | Stop the system if it smells burnt, leaks, or trips power; note the exact model and code before booking diagnosis. |
| Singapore / model note | This row is taken from the selected Daikin operation manual's remote-controller fault diagnosis table. |
| Singapore / model note | Official Daikin SM-TS3 self-diagnosis row. Manual causes: Defective radiation fin temperature thermistor; Defective inverter PCB; Defective inverter compressor. |
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 resetting P4, take a clear display photo. | Confirm which sensor P4 maps to on the exact model table. |
| Capture the Daikin indoor and outdoor model stickers so the correct family row is used. | Measure the sensor value against the service-manual resistance or voltage range. |
| Note whether one room, several rooms, or the whole system is affected, plus whether it returns after one reset. | Check connector condition, harness continuity, and PCB input before replacing boards. |
What changes the next step
These clues decide whether the first check is room-side, shared outdoor-side, refrigerant-side, source-table, or model-family confirmation.
| What you see | What it points to |
|---|---|
| Only one indoor unit shows P4. | The affected room, indoor board path, wiring route, or local component should be checked first. |
| Several rooms or the outdoor unit show the same P4 fault. | The shared outdoor side, power path, communication trunk, or refrigerant circuit needs priority checking. |
| The fault appears immediately even before the unit cools properly. | Sensor value, connector, harness, and PCB input should be tested in that order. |
| The same code appears with different meanings in the source rows. | Model family, source table, and system type decide which meaning applies before parts are quoted. |
| The model belongs to Inverter Split, Multi-Split, Ceiling Cassette rows such as EZi, iSmart ENVi. | The loaded row is source-backed by official diagnostic material. Use the matching source row before quoting parts. |
Sensor or PCB decision
Daikin P4 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.
Daikin P4 questions
What does the Daikin P4 error mean?
Can I fix a Daikin P4 error myself?
Is it safe to keep running the aircon with a P4 error?
What causes a Daikin P4 error?
Will a Daikin P4 error need a repair or a full replacement?
What should I send a technician about a Daikin P4 error?
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Read next
Use these if the quote mentions the parts, checks, or repair path this code points to.