Machine displays ER02 and does not heat or brew

Safety: Unplug the machine before any inspection. Internal components can remain hot for 30–60 minutes after use.

• Basic reset: Disconnect power for 5 minutes, then reconnect and power on. If ER02 returns immediately, the control board is not seeing a valid signal from the brew thermistor.
• External checks:
  • Ensure the machine is in a normal room-temperature environment (not in a very cold garage or outdoors).
  • Check that vents are not blocked and that the machine has not been exposed to moisture inside the housing.
• Internal sensor check (advanced):
  • Remove the top cover to access the brew thermocoil.
  • Locate the small sensor (thermistor) clipped or bonded to the thermocoil with two wires leading to the main PCB.
  • Check for a loose plug at the PCB or broken wires at the sensor.
• Repair approach: If the thermistor is physically damaged or the wiring is broken, the correct fix is to replace the brew temperature sensor / thermistor harness. This usually requires partial disassembly and careful routing of the new harness.
• When to seek service: If the wiring and sensor appear intact, the fault may be on the main control board’s sensor input circuit. This should be diagnosed and repaired by a Sage-authorized technician.