Daikin 3MXM, 4MXM and 5MXM multi-splits fault codes
Several indoor units on one outdoor unit. These add combination and addressing faults, and they are the units with the outdoor PCB LED pattern table — which is engineer territory.
Codes on the 3MXM, 4MXM and 5MXM multi-splits follow the same Daikin scheme as the rest of the range. Where a code behaves differently on this generation, the code page says so.
Daikin fault codes
Every published Daikin code. Open a code to see which models and years it applies to.
- U0Refrigerant shortage. The circuit is sealed, so if it is short it has leaked — and this is certified work by law, not a top-up.Get it checked
- A5Freeze-up protection or high pressure control. A filthy indoor filter is a legitimate published cause, which makes this the one on the list worth checking yourself.Get it checked
- U4The indoor and outdoor units have stopped talking. Daikin’s own cause list starts with the mains supply and the inter-unit cable, so one breaker cycle is worth a try before anyone is called.Get it checked
- E6The compressor failed to start. It sits in Daikin’s outdoor unit group alongside the overload and pressure codes, and all of them are certified work.Get it checked
- 00Not a fault. Daikin publish 00 as NORMAL, and it is also what shows while you are stepping through the diagnostic.Usually simple to fix