HMS 0300-1500-0001-0001: Motor-Z current sensor abnormal
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HMS 0300-1500-0001-0001 means the circuit that measures current through the Z motor has stopped reporting sensibly. It is worth being precise about what that is not: not a motor that has failed, not a stall, and not a seized lead screw. Those all have their own codes. This one is about the printer’s ability to watch, not about the thing being watched.
Affected machines: A2L and P2S. Z current sensing is what lets the printer notice that the bed has met an obstruction, so losing it removes the protection that stops a bed crash turning into bent hardware.
Where to buy
Rule out the motor, then stop
Measure the Z motor at its connector: both coil pairs should read a few ohms and match each other, with no continuity to the motor body. If it passes, the motor is healthy and no amount of replacing it will clear this code.
Then check the connector, because a high-resistance crimp can distort a current reading without breaking anything. Reseat at both ends and retry.
If the motor measures healthy and the connector is sound, the sampling circuit on the board is what failed. That is a service item. Buying a Z motor at that point is money spent on a part that was never the problem, which is exactly why the chart above puts the meter before the motor.
Printer stops with a Z motor current sensor fault, usually at power-up
Failed current sampling circuit on the board, occasionally a poor connector
- Power off at the wall and let the bed rest on its stops before working underneath it.
- Unplug the Z motor and measure resistance across both coil pairs.
- Measure from each pin to the motor body, where any continuity means a shorted winding.
- Reseat the connector at both the motor and the board, looking for a pin sitting low in its housing.
- Power up and see whether the code clears. If it does not, and the motor measured healthy, the board is the fault.
While the protection is down, avoid long unattended prints. A Z axis that meets an obstruction without current sensing will keep pushing, and the damage is to the lead screw and the bed mounts rather than to the print.
The Motor-B version of this fault is Motor-B current sensor abnormal, and the motor-side fault is abnormal Motor-Z resistance. Our page on the lead screw covers what this axis drives, and the troubleshooting index covers the rest.
HMS 0300-1500-0001-0001 FAQ
Is my Z motor failing?
Probably not. Measure it: matched coils of a few ohms with no continuity to the case means it is healthy.
Can I print with the code showing?
Short supervised prints, perhaps. Long unattended ones are unwise with the crash protection disabled.
Why does it show at power-up?
The printer self-tests its sensing circuits before it moves anything.
Could the lead screw cause it?
No. A stiff screw gives a stall or a stuck-motor code, not a sensing fault.
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