Dryer does not heat or stops with E03 error on display

Safety first: Unplug the dryer and allow it to cool completely before working near the heater.

• Clean lint filters and airflow paths: Remove and thoroughly clean the lint filter. Check the door filter (if fitted) and the base filter on Siemens heat pump models. Blocked airflow can overheat the heater and trigger E03.
• Check rear or side ventilation: For vented Siemens dryers, ensure the exhaust hose is not kinked or blocked and the wall vent flap opens freely.
• Access heater assembly: Remove the rear panel (or side panel on some condenser/heat pump models) to access the heater housing. Visually inspect for burnt spots or broken coils.
• Test heater and thermostats: With a multimeter, check continuity of the heater element terminals. Then test the high-limit thermostat and safety thermostat on the heater housing. Any open (infinite resistance) component should be replaced.
• Inspect NTC sensor: Siemens dryers use an NTC sensor near the heater or in the air duct. Check its connector and wiring. Measure resistance and compare with service data; replace if out of range.
• Reassemble and test: After replacing faulty parts, reassemble panels, restore power, and run a timed warm program to confirm heating.