Controller displays COOLANT TEMP SENSOR FAIL or ENGINE TEMP SENSOR ERROR; unit may not start or may run with limited protection.

Safety first: Turn OFF the generator and disconnect battery negative. Engine may not be protected from overheat while this fault is active.

Steps:

• Locate sensor: Find the coolant temperature sensor threaded into the cylinder head or thermostat housing on the Gillette engine.
• Inspect wiring: Check the harness from the sensor to the controller for chafing, cuts, or oil contamination. Repair damaged sections.
• Clean connector: Disconnect the sensor plug and the corresponding controller plug. Clean with electrical contact cleaner and reconnect firmly.
• Test sensor: Measure resistance across the sensor terminals and compare to the engine manufacturer’s temperature/resistance chart. Replace if out of spec.