Display shows E03 and machine shuts down; may occur during freeze cycle.

Safety first: Turn off power at the breaker. Allow hot components to cool before touching.

Steps:

• Inspect condenser and fan: Clean the condenser coil and verify the condenser fan motor runs freely and quietly when powered. Restricted airflow can cause high discharge temperatures.
• Locate discharge temperature sensor: On many Manitowoc models, the sensor is clipped to the compressor discharge line or mounted near the compressor. Check that it is firmly attached and not hanging loose.
• Check wiring harness: Inspect the sensor wiring from the sensor to the control board for cuts, pinches, or loose connectors. Reseat the connector at the control board.
• Test/replace sensor: If you have a multimeter and the service manual, compare the sensor resistance to the temperature/resistance chart. If readings are out of range, replace the discharge temperature sensor.

When to call a technician: If the sensor and wiring are good but E03 persists, a refrigeration problem (overcharge, restriction, or compressor issue) may be causing high discharge temperatures. This requires a professional.