Freezer shows E22 and may not maintain set temperature; compressor cycles may be abnormal.

Safety: Disconnect mains power before accessing the control board.

• 1. Hard reset: Unplug the freezer for at least 15 minutes to fully discharge the control electronics, then reconnect and observe if E22 returns.
• 2. Check for surge damage: Remove the control cover and inspect the PCB for burn marks, cracked ICs, or damaged tracks.
• 3. Listen for relays: When power is restored, listen for relay clicks indicating compressor and fan control. Lack of relay activity with E22 present suggests board failure.
• 4. Verify sensors and loads: Ensure that major loads (compressor, fan, heaters) are not shorted, as this can damage the board. If in doubt, have a technician test them.
• 5. Replace control board: If E22 persists and physical damage is evident or functions are erratic, replace the main control board with a Siemens-approved part. Transfer any configuration plugs or EEPROMs as per service documentation.
• 6. Reprogram if required: Some models require configuration after board replacement; follow Siemens instructions or have a technician perform this.

Warning: Board-level component repair is not recommended for untrained users due to mains voltage and complexity.