Dryer displays E09 and does not heat; on heat pump models, compressor does not run.

Safety first: Unplug the dryer. Heat pump systems contain high-pressure refrigerant; do not open sealed system components unless certified.

• Confirm model type: Verify that your Gaggenau dryer is a heat pump model (often indicated on the rating plate or in the manual).
• Check airflow and filters: Ensure lint filter and condenser (if user-accessible) are clean. Restricted airflow can cause overheat faults.
• Listen for compressor: Start a cycle and listen for the compressor starting after a few minutes. If it never starts, proceed with electrical checks.
• Inspect wiring to heat pump module: With power off, access the base of the dryer and check connectors to the compressor, inverter board, and temperature sensors.
• Check thermal fuses: Test any thermal fuses or thermostats in the heat pump circuit for continuity. Replace if open.
• Professional service: If electrical components test good but E09 persists, the compressor or sealed system may be faulty. This requires specialized tools and should be handled by an authorized Gaggenau service technician.