Display shows ERR4 immediately on power-up; grill will not start any cooking cycle.

Safety first: Unplug the grill before accessing wiring or the control panel.

• Locate RTD probe: On Gourmet Grillson pellet grills, the RTD (grill temperature sensor) is typically a small metal probe protruding into the cook chamber from the side wall.
• Inspect physically: Check if the probe is bent, broken, or heavily corroded. Ensure the probe body is firmly mounted and not loose.
• Check connections: Trace the RTD cable from the probe into the control panel area. Confirm the connector is fully seated on the main control board and that there are no cuts or pinch points in the cable.
• Test continuity: Disconnect the RTD from the board and measure resistance with a multimeter. At room temperature, you should see a finite resistance (often 100–1000 Ω depending on sensor type). Infinite resistance indicates an open sensor that must be replaced.
• Replace RTD probe: Remove the mounting screw or nut holding the probe to the cook chamber wall. Install the new RTD in the same location, route the cable away from hot surfaces, and reconnect to the control board.
• Power up and test: Plug in the grill and verify that ERR4 is cleared and ambient temperature is displayed correctly.