Freezer displays E4 and may stop cooling or cycle erratically; compressor may not start.

Safety: Disconnect power before opening the control panel or top cover.

Steps:

• 1. Locate ambient sensor: On many Toshiba freezers, the ambient sensor is located behind the front display/control panel or in the top hinge area, sensing room temperature.
• 2. Remove control panel: Carefully pry off the control panel bezel or remove screws as needed. Avoid damaging the ribbon cable.
• 3. Inspect sensor and wiring: Look for a small thermistor probe or plastic-encased sensor. Check for loose connectors, corrosion, or broken wires.
• 4. Test resistance: Disconnect the sensor and measure resistance at room temperature. Compare to typical NTC values. Replace if open, shorted, or significantly off-spec.
• 5. Check PCB connector: Reseat the sensor connector on the main PCB. If the sensor tests good but E4 persists, the PCB input may be defective.
• 6. Replace faulty part: Install a new Toshiba-compatible ambient thermistor or replace the main control PCB if necessary.

Tip: Ensure the freezer is not installed in an area outside the specified ambient temperature range, as extreme conditions can also cause sensor-related errors.