Kubota standby generator shows E20 and will not start; log indicates 'Intake Air Heater Fault' on some cold-climate models.

Safety first: Turn OFF the generator and disconnect the battery negative cable. The intake heater circuit carries high current.

• Check fuse: Locate the intake air heater fuse and test it with a multimeter. Replace if blown and investigate for shorts.
• Inspect wiring: Follow the heavy cables from the relay to the intake heater element. Look for chafed insulation or contact with sharp edges.
• Test heater element: Disconnect the heater and measure resistance across its terminals. Compare to Kubota specifications; an open circuit indicates a failed element.
• Relay operation: With battery reconnected, command a preheat cycle and listen for the relay click. Measure voltage at the heater terminals; if none, replace the relay.
• Cold start performance: After repair, verify that the generator starts reliably in cold conditions and that E20 is cleared.