HMS 0300-3A00-0001-0001: right side auxiliary fan slow or stopped
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HMS 0300-3A00-0001-0001 means the right side auxiliary fan on a P2S or X2D is running below its commanded speed, or has stopped. This is the large fan that handles component cooling and filtration, not the small one on the hotend. The two usual causes are an obstruction and a connector that is not fully seated.
Affected machines: P2S and X2D. On enclosed machines this fan does two jobs at once, moving air across components and pulling it through the filter. That makes it the fan that collects the most dust in the whole printer.
Where to buy
Slow and stopped are different problems
A fan reporting slow has picked up drag, and drag is nearly always something you can remove: dust packed into the hub, a filament wisp round the shaft, or a filter so loaded that the blades are fighting a wall of air. All three are free to fix.
A fan reporting zero is a different matter, but even then the connector deserves a look before the fan is condemned. This assembly sits where panels are removed and refitted, and a plug that is half seated behaves exactly like a dead fan.
Printer reports the right side auxiliary fan is slow or stopped, sometimes with a warmer chamber
Dust or debris in the fan, a loaded filter, a loose connector, occasionally a failed fan
- Power off at the wall and let the printer cool before removing any panel.
- Find the right side fan and look through the blades with a torch for filament wisps and packed dust.
- Spin the fan by hand. It should turn freely and coast rather than stopping dead.
- Remove and clean or replace the filter on that air path. A loaded filter loads the fan.
- Unplug and reseat the fan connector, checking the pins in both halves of the plug.
- Power up and watch the fan start. If it still reports slow with a clean, free blade, fit the replacement.
Order by machine. The auxiliary fans for the H2 series and for the P2S are different assemblies at different prices, and neither is the small hotend fan that most search results will offer you first.
The same fault on the H2D and other machines is the right-side auxiliary fan code. Our pages on cooling fans and enclosed printers explain what this air path is for, and the troubleshooting index covers the rest.
HMS 0300-3A00-0001-0001 FAQ
Is this the hotend fan?
No. This is the large auxiliary fan on the right side, and it costs several times what a hotend fan does.
Can I print while it is faulty?
Short PLA prints, probably. Anything relying on chamber management or filtration should wait.
Will a new filter clear the code?
Often, yes. A loaded filter is the most common cause of a fan reporting below its commanded speed.
Why is this fan expensive?
It is a high-airflow assembly with its own housing and tachometer rather than a bare blower.
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