Display shows ERR1 and brewing will not start or stops immediately on KitchenAid digital drip coffee maker.

Safety first: Unplug the coffee maker before inspecting parts. Allow the unit to cool completely if recently used.

Step-by-step checks:

• Reseat the water reservoir: Remove the water tank, empty it, then firmly reinstall it. Make sure it clicks or sits flush against the back of the machine. Many KitchenAid coffee makers use a small magnet or tab on the reservoir to signal presence.
• Check for obstructions: Inspect the reservoir base and the machine’s reservoir cavity for coffee grounds, scale, or plastic debris that may prevent full seating.
• Inspect the reservoir magnet/float: On some KitchenAid models, a small magnet or floating indicator in the reservoir triggers a reed switch. Verify the float moves freely and is not stuck by mineral deposits. Clean with warm water and mild dish soap.
• Clean the reservoir sensor area: Wipe the area where the reservoir meets the machine with a damp cloth to remove scale or residue that may interfere with the sensor.
• Power reset: With the unit unplugged, wait 5 minutes, then plug back in and test. Sometimes the control board needs a reset after a sensor error.

If the error persists: The internal reservoir presence switch or reed sensor on the main control board may be faulty. Replacement of the sensor or control board is typically a level 4–5 repair and may require a professional technician.