Unit displays E25; may be associated with abnormal outdoor ambient temperature readings.

Safety first: Turn off power at the outdoor disconnect before working on the unit.

• Step 1 – Locate ambient sensor: Find the small sensor usually mounted near the outdoor air intake grille.
• Step 2 – Inspect mounting and wiring: Ensure the sensor is exposed to outdoor air (not touching hot pipes) and the cable is intact.
• Step 3 – Check connector: Verify the sensor plug is firmly connected to the outdoor PCB.
• Step 4 – Measure resistance: Disconnect and measure resistance, comparing to Toshiba’s chart for the current outdoor temperature. Replace if readings are abnormal.
• Step 5 – Replace sensor: Install a new ambient temperature sensor and secure it in the original location.