Oven beeps and displays E1, will not start any cooking program.

Safety first: Disconnect the oven from mains power before removing any panels or testing continuity.

• Locate the sensor: Inside the Tristar oven cavity, find the small metal probe (NTC sensor) usually mounted on the rear wall with two screws.
• Check wiring and connector: Remove the rear cover of the oven to access the sensor wiring. Ensure the two-wire harness from the sensor to the main control board is intact and firmly connected. Reseat the connector on the PCB.
• Test sensor resistance: Disconnect the sensor and measure its resistance with a multimeter at room temperature. Typical NTC sensors read around 1000–1100 Ω at 25°C (consult Tristar service data if available). An infinite reading indicates an open sensor.
• Replace if faulty: If the sensor is open or far out of spec, replace it with a genuine Tristar oven NTC temperature sensor. Transfer any mounting brackets and reinstall using the original screws.

After replacement, restore power and clear the error by performing a power reset. If E1 persists with a known-good sensor, the main control PCB may have a defective sensor input circuit.