Daikin split system air conditioner code L4: Inverter heatsink overheating
Split system air conditioner, Australia
The inverter circuit heatsink (radiation fin) got too hot.
This needs a licensed air conditioning technician. There is nothing safe to check yourself. Leave the covers on and book a professional.
What causes it
-
The inverter heatsink keeps overheating. A licensed technician must find why.
How to read this code on your unit
A fault shows as a blinking lamp on the indoor unit, the OPERATION lamp on most models or the multi-monitor lamp on Zena FTXJ-PVMA. To read the code, point the remote at the indoor unit and hold its Cancel button for about 5 seconds, until 00 blinks in the temperature display section. Then press Cancel again and again until the remote answers with a long beep; the code in the temperature display at that moment is the stored fault. A short beep means the code on show is not a stored fault. To clear the display, hold Cancel for 5 seconds, or leave the remote untouched for a minute. The manuals say a fault must be handled by a licensed installer or the dealer, so write the code down before you call.
Booking a licensed air conditioning technician
Book a licensed air conditioning technicianlicensed air conditioning technician
- Do not open any panels. Refrigerant circuits must only be opened by a licensed technician.
- Note the code, which unit shows it (indoor or outdoor), and the model numbers of both units.
- Book a licensed air conditioning technician and give them those details.
Models that show this code
167 models in 21 ranges
| Range | Models |
|---|---|
| Alira FTXM-UVMA | FTXM20UVMA, FTXM25UVMA, FTXM35UVMA, FTXM46UVMA, FTXM50UVMA, FTXM60UVMA, FTXM71UVMA |
| Alira X FTXM-W1VMA | FTXM20W1VMA, FTXM25W1VMA, FTXM35W1VMA, FTXM46W1VMA, FTXM50W1VMA, FTXM60W1VMA, FTXM71W1VMA |
| Alira X FTXM/FTKM-W2VMA | FTXM20W2VMA, FTXM25W2VMA, FTXM35W2VMA, FTXM46W2VMA, FTXM50W2VMA, FTXM60W2VMA, FTXM71W2VMA, FTKM20W2VMA, FTKM25W2VMA, FTKM35W2VMA, FTKM46W2VMA, FTKM50W2VMA, FTKM60W2VMA, FTKM71W2VMA |
| Alira X FTXM/FTKM-WVMA | FTXM20WVMA, FTXM25WVMA, FTXM35WVMA, FTXM46WVMA, FTXM50WVMA, FTXM60WVMA, FTXM71WVMA, FTKM20WVMA, FTKM25WVMA, FTKM35WVMA, FTKM46WVMA, FTKM50WVMA, FTKM60WVMA, FTKM71WVMA |
| Cora FTKM-Q2VMA | FTKM20Q2VMA, FTKM25Q2VMA, FTKM35Q2VMA, FTKM46Q2VMA, FTKM50Q2VMA, FTKM60Q2VMA, FTKM71Q2VMA |
| Cora FTXM/FTKM-QVMA and FTXM-PVMA | FTXM20QVMA, FTXM25QVMA, FTXM35QVMA, FTXM46QVMA, FTXM50QVMA, FTXM60QVMA, FTXM71QVMA, FTKM20QVMA, FTKM25QVMA, FTKM35QVMA, FTKM46QVMA, FTKM50QVMA, FTKM60QVMA, FTKM71QVMA, FTXM85PVMA, FTXM95PVMA |
| Cora FTXV-UVMA | FTXV20UVMA, FTXV25UVMA, FTXV35UVMA, FTXV46UVMA, FTXV50UVMA, FTXV60UVMA, FTXV71UVMA |
| Cora FTXV-W1VMA | FTXV20W1VMA, FTXV25W1VMA, FTXV35W1VMA, FTXV46W1VMA, FTXV50W1VMA, FTXV60W1VMA, FTXV71W1VMA |
| Cora FTXV-W2VMA | FTXV20W2VMA, FTXV25W2VMA, FTXV35W2VMA, FTXV46W2VMA, FTXV50W2VMA, FTXV60W2VMA, FTXV71W2VMA |
| Cora FTXV-WVMA | FTXV20WVMA, FTXV25WVMA, FTXV35WVMA, FTXV46WVMA, FTXV50WVMA, FTXV60WVMA, FTXV71WVMA |
| Lite FTKF-T2VMA | FTKF20T2VMA, FTKF25T2VMA, FTKF35T2VMA, FTKF46T2VMA, FTKF50T2VMA, FTKF60T2VMA, FTKF71T2VMA |
| Lite FTKF-TVMA | FTKF20TVMA, FTKF25TVMA, FTKF35TVMA, FTKF46TVMA, FTKF50TVMA, FTKF60TVMA, FTKF71TVMA |
| Lite FTXF-TVMA | FTXF20TVMA, FTXF25TVMA, FTXF35TVMA, FTXF46TVMA, FTXF50TVMA, FTXF60TVMA, FTXF71TVMA |
| Lite FTXF-W1VMA | FTXF20W1VMA, FTXF25W1VMA, FTXF35W1VMA, FTXF46W1VMA, FTXF50W1VMA, FTXF60W1VMA, FTXF71W1VMA |
| Lite FTXF-W2VMA | FTXF20W2VMA, FTXF25W2VMA, FTXF35W2VMA, FTXF46W2VMA, FTXF50W2VMA, FTXF60W2VMA, FTXF71W2VMA |
| Lite FTXF-WVMA | FTXF20WVMA, FTXF25WVMA, FTXF35WVMA, FTXF46WVMA, FTXF50WVMA, FTXF60WVMA, FTXF71WVMA |
| XL 85/95 P2VMA/L2VMA | FTXM85P2VMA, FTXM95P2VMA, FTXV85L2VMA, FTXV95L2VMA |
| XL 85/95 PAVMA/LVMA | FTXM85PAVMA, FTXM95PAVMA, FTKM85PAVMA, FTKM95PAVMA, FTXV85LVMA, FTXV95LVMA |
| Zena FTXJ-PVMA | FTXJ25PVMAW, FTXJ35PVMAW, FTXJ50PVMAW, FTXJ25PVMAS, FTXJ35PVMAS, FTXJ50PVMAS |
| Zena FTXJ-T2VMA | FTXJ25T2VMAW, FTXJ35T2VMAW, FTXJ50T2VMAW, FTXJ60T2VMAW, FTXJ25T2VMAK, FTXJ35T2VMAK, FTXJ50T2VMAK, FTXJ60T2VMAK |
| Zena FTXJ-TVMA | FTXJ25TVMAW, FTXJ35TVMAW, FTXJ50TVMAW, FTXJ60TVMAW, FTXJ25TVMAK, FTXJ35TVMAK, FTXJ50TVMAK, FTXJ60TVMAK |
Where this comes from
- Zena FTXJ25/35/50PVMA operation manual (3P369488-1) , page 38
- Zena FTXJ25-60TVMA operation manual (3P524249-1) , page 23
- Zena FTXJ25-60T2VMA operation manual (3P705032-1) , page 23
- XL FTXM/FTXV/FTKM 85/95 operation manual (3P552666-7B, 3P552666-10D) , page 35
- Alira X FTXM20-60WVMA operation manual (3P651499-1, 3P651499-2) , page 47
- Lite FTXF20-60TVMA operation manual (3P372379-11R, 3P372379-12Q, 3P372379-16N, 3P372379-17N) , page 27, 91
Checked against the manufacturer's manual on 17 October 2026.
Other Daikin split system air conditioner codes
| Code | Meaning | What you can do |
|---|---|---|
| H8 | DC current or voltage sensor fault | Call a pro |
| H9 | Outdoor air temperature sensor fault | Call a pro |
| J3 | Discharge pipe sensor fault | Call a pro |
| J6 | Outdoor coil temperature sensor fault | Call a pro |
| J8 | Liquid pipe sensor fault | Call a pro |
| L3 | Electrical parts overheating | Call a pro |
| L5 | Inverter output overcurrent | Call a pro |
| P4 | Heatsink temperature sensor fault | Call a pro |
| U0 | System short of refrigerant | Call a pro |
| U2 | Supply voltage out of range | Call a pro |
| U4 | Indoor-outdoor communication fault | Call a pro |
| UA | Mismatched indoor and outdoor units | Call a pro |