Display shows H23, ice build-up around evaporator, poor cooling performance

Safety: Unplug the refrigerator before removing freezer or refrigerator rear panels.

• Step 1 – Access evaporator: Remove drawers and rear panel in the affected compartment (often freezer). Locate the defrost thermistor clipped to the evaporator tubing.
• Step 2 – Check mounting: Ensure the thermistor is firmly attached to the coil; a loose sensor can misread temperature and trigger H23.
• Step 3 – Inspect wiring: Look for brittle insulation, breaks, or connectors pulled loose. Reseat the connector.
• Step 4 – Test thermistor: Use a multimeter to measure resistance at freezer temperature. Compare to Panasonic specifications (typically higher resistance at lower temperatures). Replace if open, shorted, or far out of range.
• Step 5 – Replace sensor: Install a new defrost/evaporator thermistor, clip it securely to the coil, and route wiring away from heater elements. Reassemble and restore power.