Codes differ by manufacturer, and the underlying faults are almost always from the same short list.
Water problems
The most common category. The machine reports an empty tank, or refuses to start.
Tank not seated. Push it firmly; there is a spring valve underneath that must open.
Airlock. After running dry, the pump cannot prime. Run water through the steam wand or hot-water tap for a few seconds.
Float or sensor fouled. Scale and residue can stop a float moving or confuse a conductivity sensor. Also why distilled water sometimes reads as empty.
Brew unit
Not seated. On removable-unit machines, the unit must click home or the machine refuses to brew. Turn it so the arrows align.
Jammed. Grounds behind the unit block its travel. Remove, rinse, clear the cavity.
Scale and maintenance prompts
Not faults. The machine has counted litres or cycles and wants descaling or cleaning. Ignoring them is how machines die.
Temperature sensor
Rarer, and it needs service. If the machine reports overheating or fails to heat, stop using it.
Before calling anyone
Unplug for five minutes. A surprising number of codes are transient states cleared by a power cycle — and it costs nothing to try.
Last reviewed 8 August 2026