E09 error; freezer may shut down cooling or operate erratically.

Safety: Unplug the freezer before accessing the control module. Electronic boards are sensitive to static; avoid touching components unnecessarily.

Steps:

• Power reset: Disconnect power for 10–15 minutes, then reconnect. If E09 returns immediately, the board is likely faulty.
• Visual inspection: Locate the main control module (often in a housing at the top front or rear). Remove the cover and inspect for burnt components, bulging capacitors, or scorch marks.
• Check connectors: Ensure all harness connectors are fully seated and free of corrosion.
• Surge protection: If the error followed a power outage or surge, consider using a surge protector after repair.
• Replace control module: If visible damage is present or diagnostics indicate board failure, replace the main control module with the exact Bosch part number. Transfer any configuration jumpers as per service documentation.

Important: Some Bosch models may require configuration or programming after board replacement. This is best handled by an authorized technician.