Nuova Simonelli Aurelia II Message DOSER ERROR: No Doser Pulses
DOSER ERROR on a Nuova Simonelli Aurelia II (Digit, V and S) means the doser sent no pulses during the first 3 seconds of a delivery. If nobody stops the delivery by hand, it blocks at the 120 second limit. Interrupt the delivery, make sure the portafilter is not packed too tightly and the group screen is clean, then try one more shot.
Medium: that group cannot dose shots reliably until the cause is found, though the machine itself is working.
- Code
- DOSER ERROR
- Maker
- Nuova Simonelli
- Equipment
- Espresso machines
- Applies to
- Aurelia II Digit / V / S
What does Nuova Simonelli DOSER ERROR mean?
The doser is the flowmeter that measures the water for each shot, and it must start sending pulses almost as soon as the pump pushes water through the group. The control looks for those pulses in the first 3 seconds of a delivery. If none arrive, it shows DOSER ERROR. Without pulses the machine cannot dose a shot, because it has no way to know how much water has passed. If nobody stops the delivery by hand, it blocks at the 120 second limit. Often the doser is fine and the water simply cannot move: a portafilter packed too tightly or a group screen clogged with coffee oils holds the flow back until the turbine in the doser stays still. In other cases the doser signal or its wiring has failed, the doser itself has stopped, or the pump pressure at the group is too low. The first practical test is to see whether water flows freely with the portafilter removed. A free flow with no pulses points to the doser and its wiring.
Affected models and control systems
This applies to Nuova Simonelli Aurelia II machines in the Digit, V and S versions (User Handbook, March 2012).
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- Water flowing but the shot not stopping
- DOSER ERROR on the display
- Delivery that has to be stopped by hand
- Little or no water at the group
Possible causes
Listed in Nuova Simonelli's documentation
- Doser signal or its wiring failed
- Packed or blocked group screen
- Doser itself stopped
- Pump pressure at the group too low
Other likely causes — what usually sits behind DOSER ERROR on this control. A technician confirms which one it is before any part is replaced.
- Scale in the doser turbine
- Portafilter basket overdosed so water cannot pass
- Pump weak after long use, so flow barely turns the doser
Safe checks before calling for service
- Interrupt the delivery, as the owner's manual directs.
- Check that the portafilter is not packed too tightly and that the group screen is clean.
- Try one more shot after you clear the message.
- If DOSER ERROR returns, call us and tell us which group and whether water flowed freely without coffee.
How a technician diagnoses DOSER ERROR
- Read the message and note the group.
- Run water without the portafilter and watch the flow.
- Inspect the group screen and shower.
- Check the doser signal and wiring to the control.
- Measure pump pressure at the group.
- Replace the doser only after these checks.
- The doser and pump are inside the machine with live wiring and hot water.
- Pump pressure checks need a gauge and care with hot parts.
- Separating a blocked flow from a failed doser takes a flow test.
How DOSER ERROR differs from similar codes
DELIVERY ERROR waits for the full 120 second limit. DOSER ERROR flags missing pulses within 3 seconds.
Technical reference
- Document
- Aurelia II (S, V, Digit) User Handbook March 2012, Function Messages p.75-78
- Edition
- March 2012 (Marzo 2012); no part number printed
- Models / control
- Aurelia II Digit / V / S
- Section
- 10. Aurelia Digit Machine Function Messages, p. 75-76 (messages listed as DIAGNOSIS OF ERROR, DELIVERY ERROR, DOSER ERROR, LEVEL ERROR, PRESSURE ERROR, OVERCURRENT ERR., FINE GRINDING, COARSE GRINDING); 11. Aurelia V, p. 77; 12. Aurelia S, p. 78
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Nuova Simonelli espresso machine error codes
Why does DOSER ERROR say 3 seconds?
That is how long the control waits for the first pulses before it flags a missing signal.
Is a packed portafilter really enough?
Yes. If water cannot move, the doser cannot count.
What if it returns?
Then the doser, wiring or pump needs testing.
Need help with Nuova Simonelli DOSER ERROR?
A technician confirms the cause on site and gives you the price in writing before any work starts.