F4 error appears, oven may not heat correctly or may shut down

Safety first: Turn off power at the breaker before testing.

• Inspect sensor and wiring: Look for melted insulation or signs of a short where the sensor wiring passes through the rear wall.
• Measure resistance: Disconnect the oven temperature sensor and measure resistance at room temperature. A reading near 0 Ω indicates a shorted sensor. Replace it.
• Check harness for shorts: With the sensor disconnected at both ends, test each conductor to chassis ground and to each other. Any continuity indicates a short; repair or replace the harness.
• Control board: If sensor and harness are good but F4 persists, the sensor input circuit on the electronic oven control board may be shorted internally. Replace the board.