C2 error appears when trying to start a cooking program, often accompanied by no heating.

Safety first: Unplug the appliance. The heater circuit carries mains voltage; do not work on it while connected.

• Check for obvious damage: Remove the bowl and inspect the base for burn marks or a burnt smell. If present, do not power the unit again until inspected by a professional.
• Ventilation and cooling: Allow the unit to cool and then try a simple low-temperature program (e.g., 37°C) to see if the error reappears immediately. Persistent C2 indicates a hardware fault.
• Advanced continuity check: With the bottom cover removed and unit unplugged, measure resistance across the heater terminals. An open circuit (infinite resistance) or a very low resistance (near short) indicates a failed heater block.
• When to call a technician: Replacing the heater block or main PCB requires disassembling the motor/heat tower and dealing with high-voltage wiring. This should be performed by an authorized Thermomix service center.